Add two more Unit tests for get_is_peer(), and add lhc_am link flag to map_to_peer tests

[facao]

No description provided.

[whchung]

@facao there are conflicts in this pull request. please help fix them. also it would be good if you provide:

• "HCC_RUNTIME=HSA make test" results to ensure tests you provide could all pass, and don't cause other side effects
• HIP test results to show these new APIs do help HIP tests pass

[facao]

[100%] Running HCC regression tests
llvm-lit: lit.cfg:115: note: using clang: '/home/user1/git/roc-1.0/hcc/build/compiler/bin/clang'
Testing Time: 101.99s
Expected Passes : 20
Expected Failures : 1
[100%] Built target test

This commit add two Unit tests, did not add new APIs.