[llvm] RenameIndependentSubregs: Add missing sub-range for new IMPLICIT_DEFs (PR #89050)

[Jay Foad via llvm-commits]

jayfoad wrote:

What was the effect of the bug? Was it failing MachineVerifier, or just generating incorrect code? Do you have a small test case? Or do the tests updated in this PR show the fix - and if so, can you point out where?

https://github.com/llvm/llvm-project/pull/89050