CircleCI caching: allow ftime to be ceil(ftime_req) in Base.stale_cac…

…hefile (#47433)

* CircleCI caching: allow ftime to be ceil(ftime_req) in Base.stale_cachefile

It appears that [caching functionalities](https://circleci.com/docs/caching/) provided by CircleCi, a leading CI/CD provider, can truncate timestamps to full seconds, resulting in re-compilations as below:
```
Rejecting stale cache file /root/.julia/compiled/v1.8/ComponentArrays/cYHSD_3rQji.ji (mtime 1.6673960929277816e9) because file /root/.julia/packages/ComponentArrays/YyD7i/src/ComponentArrays.jl 
```

This PR relaxes the `is_stale` check to be robust against rounding-to-second timestamp mutations.

I can provide a minimal CircleCI configuration file to reproduce if this is helpful.

base/loading.jl

@@ -2260,6 +2260,7 @@ end
                 ftime = mtime(f)
                 is_stale = ( ftime != ftime_req ) &&
                            ( ftime != floor(ftime_req) ) &&           # Issue #13606, PR #13613: compensate for Docker images rounding mtimes
+                           ( ftime != ceil(ftime_req) ) &&            # PR: #47433 Compensate for CirceCI's truncating of timestamps in its caching
                            ( ftime != trunc(ftime_req, digits=6) ) && # Issue #20837, PR #20840: compensate for GlusterFS truncating mtimes to microseconds
                            ( ftime != 1.0 )  &&                       # PR #43090: provide compatibility with Nix mtime.
                            !( 0 < (ftime_req - ftime) < 1e-6 )        # PR #45552: Compensate for Windows tar giving mtimes that may be incorrect by up to one microsecond