[llvm-branch-commits] [CodeGen] Fix non-determinism in MachineBlockHashInfo hashes (PR #192826)

[Vitaly Buka via llvm-branch-commits]

https://github.com/vitalybuka created https://github.com/llvm/llvm-project/pull/192826

The previous implementation used `hash_value(MachineOperand)`, which
is not guaranteed to be stable across different executions because it
hashes pointers for certain operand types (like MBB, GlobalAddress, etc).

Pointer members of MachineOperand not hashed now, but it's not worse that
random pointer value from before.

Fixes #173933.