[llvm] [InstCombine] Propagate invariant.load metadata across unpacked loads (PR #152186)

[Vedant Paranjape via llvm-commits]

VedantParanjape wrote:

This change seems to crash the following testcase:

```  
-- Testing: 60849 tests, 64 workers --
  Testing:  0.. 10.. 20.. 30..
  FAIL: LLVM :: CodeGen/Thumb2/mve-vcvt-fixed-to-float.ll (23899 of 60849)
  ******************** TEST 'LLVM :: CodeGen/Thumb2/mve-vcvt-fixed-to-float.ll' FAILED ********************
  Exit Code: 1
  ```

https://github.com/llvm/llvm-project/pull/152186