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

[Joseph Huber via llvm-commits]

jhuber6 wrote:

> > pretty much just found that loading binaries in parallel would crash depending on the machine
> 
> This sounds like a loader issue. CC @kzhuravl

Who knows, maybe they fixed it, haven't checked in awhile.

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