[llvm] [Offload][cmake] Add GPU test job limit for AMDGPU buildbot cmake cache (PR #146611)

[Joseph Huber via llvm-commits]

jhuber6 wrote:

> Thanks for the help @jhuber6! I might not have full context here, you mean enabling this flag may not be safe?

Yes, the HSA runtime would routinely crash when many of these tests were run in parallel. I poked at it through https://github.com/jhuber6/hsa_test awhile back, pretty much just found that loading binaries in parallel would crash depending on the machine.

https://github.com/llvm/llvm-project/pull/146611