[llvm] [MachineLICM] Do not rely on hasSideEffect when handling impdefs (PR #145379)

[Anatoly Trosinenko via llvm-commits]

atrosinenko wrote:

Fixed the test failures: the original fix ruled out safe-to-move instructions with `dead implicit-def` operands. Fixed this in 079d654b05a4b0b98fc6f137f0d3588543039153 and updated precommitted test cases accordingly.

https://github.com/llvm/llvm-project/pull/145379