[clang] [llvm] [AMDGPU] Make cluster a target feature (PR #162040)

[Jordan Rupprecht via llvm-commits]

rupprecht wrote:

Running LLVM tests downstream w/ sanitizers, I'm seeing `llvm/lib/Target/AMDGPU/GCNSubtarget.h:1842:37: runtime error: load of value 171, which is not a valid value for type 'bool'`, e.g. for tests like lld/test/ELF/lto/r600.ll. I'm not sure why I can't find similar failures on sanitizer buildbots, though I don't see why it wouldn't affect those. Is there something needed to make default initialization happen for this feature?

https://github.com/llvm/llvm-project/pull/162040