[llvm] [AMDGPU] Fix mir-canon-multi-def.mir test (PR #173243)

[Frederik Harwath via llvm-commits]

frederik-h wrote:

This test introduced in #172982 fails on s390x. It seems that the stable hashing is not as stable as I assumed. It does not seem to take endianness into account. Should this be fixed?

https://github.com/llvm/llvm-project/pull/173243