[llvm] [WebAssembly] Fix operand order in performBitcastCombine (PR #190361)

[Jasmine Tang via llvm-commits]

badumbatish wrote:

this seems like the CI is failing because the PR's modifying the llc's output that filecheck's expecting. In this case you should update the file with a command like 
```
ninja -C build && llvm/utils/update_llc_test_checks.py --llc-binary ./build/bin/llc llvm/test/CodeGen/WebAssembly/masked-shifts.ll
```

https://github.com/llvm/llvm-project/pull/190361