[llvm] [Remarks] Introduce tool to count remarks. (PR #66214)

[Jan Patrick Lehr via llvm-commits]

jplehr wrote:

This appears to have broken the AMDGPU OpenMP buildbot https://lab.llvm.org/buildbot/#/builders/193/builds/39996 and the Clang HIP buildbot https://lab.llvm.org/buildbot/#/builders/165/builds/44145

https://github.com/llvm/llvm-project/pull/66214