Report URL should be unique

[maleadt]

After removing the report repo's HEAD SHA to the report URL, so that we can rewrite its history, we did cause multiple reports of the same PR to overwrite one another: JuliaLang/julia#37214 (comment)

We should probably include some random bit, or increment a counter to make the key unique.

[vtjnash]

Alternatively we could have that URL include the commit hash

[maleadt]

This probably causes an issue reported by @vtjnash:

      From worker 3:      19fe4202d72 upload report for BenchmarkJob JuliaLang/julia@ec47740 vs. JuliaLang/julia@1ee253d                                  
      From worker 3:                                                                                                                                      
      From worker 3:    If you want to keep it by creating a new branch, this may be a good time                                                          
      From worker 3:    to do so with:                                                                                                                    
      From worker 3:                                                                                                                                            From worker 3:     git branch <new-branch-name> 19fe4202d72                                                                                               From worker 3:                                                                                                                                      
      From worker 3:    Switched to branch 'master'                                                                                                       
      From worker 3:    Your branch is up to date with 'origin/master'.                                                                                   
      From worker 3:    Fetching origin                                                                                                                   
      From worker 3:    From https://github.com/JuliaCI/NanosoldierReports                                                                                
      From worker 3:       45ea81d6d5d..4dc519d6eb9  master     -> origin/master                                                                          
      From worker 3:       2cf9410941a..f19f563e468  gh-pages   -> origin/gh-pages                                                                        
      From worker 3:    HEAD is now at 4dc519d6eb9 upload report for PkgEvalJob JuliaLang/julia@b07484c [2023-01-12]                                      
      From worker 3:    Auto-merging benchmark/by_hash/ec47740_vs_1ee253d/data.tar.zst                                                                    
      From worker 3:    Auto-merging benchmark/by_hash/ec47740_vs_1ee253d/logs/1ee253d3291728fc74051aff7cd6a5ed02b9f77d_against.out                       
      From worker 3:    Auto-merging benchmark/by_hash/ec47740_vs_1ee253d/logs/1ee253d3291728fc74051aff7cd6a5ed02b9f77d_build.err                         
      From worker 3:    Auto-merging benchmark/by_hash/ec47740_vs_1ee253d/logs/1ee253d3291728fc74051aff7cd6a5ed02b9f77d_build.out                         
      From worker 3:    Auto-merging benchmark/by_hash/ec47740_vs_1ee253d/logs/ec4774049d7a30228cdea28a921f0fcb0bbb2d46_build.err                         
      From worker 3:    Auto-merging benchmark/by_hash/ec47740_vs_1ee253d/logs/ec4774049d7a30228cdea28a921f0fcb0bbb2d46_build.out                         
      From worker 3:    Auto-merging benchmark/by_hash/ec47740_vs_1ee253d/logs/ec4774049d7a30228cdea28a921f0fcb0bbb2d46_primary.out                       
      From worker 3:    Auto-merging benchmark/by_hash/ec47740_vs_1ee253d/report.md                                                                       
      From worker 3:    The previous cherry-pick is now empty, possibly due to conflict resolution.                                                       
      From worker 3:    If you wish to commit it anyway, use:                                                                                             
      From worker 3:                                                                                                                                      
      From worker 3:        git commit --allow-empty                                                                                                      
      From worker 3:                                                                                                                                      
      From worker 3:    Otherwise, please use 'git cherry-pick --skip'                                                                                    
      From worker 3:    On branch master                                                                                                                  
      From worker 3:    Your branch is up to date with 'origin/master'.                                                                                   
      From worker 3:                                                                                                                                      
      From worker 3:    You are currently cherry-picking commit 19fe4202d72.                                                                              
      From worker 3:      (all conflicts fixed: run "git cherry-pick --continue")                                                                         
      From worker 3:      (use "git cherry-pick --skip" to skip this patch)                                                                               
      From worker 3:      (use "git cherry-pick --abort" to cancel the cherry-pick operation)                                                             
      From worker 3:                                                                                                                                      
      From worker 3:    nothing to commit, working tree clean                                                                                             
┌ Info: [Node 3 | 2023-01-13T10:13:41.368]: failed job: BenchmarkJob JuliaLang/julia@3c6c967 vs. JuliaLang/julia@1ee253d                                  
│ On worker 3:                                                               
│ NanosoldierError: error when preparing/pushing to report repo: failed process: Process(setenv(`/home/nanosoldier/.julia/artifacts/33c5e3a13ad6427f86436f

@maleadt I needed to fix this manually

rm -r benchmark/by_hash/ec47740_vs_1ee253d/
git add -u
git commit -m temporary
git cherry-pick -n <>
git commit --am -C <>

Originally posted by @vtjnash in JuliaLang/julia#48257 (comment)