[llvm] [X86] Resolve FIXME: Copy kill flag for eflags (PR #82411)

[via llvm-commits]

AtariDreams wrote:

> Do you think we should we consider altering the findRegisterDefOperandIdx/findRegisterDefOperand argument order and require the TRI pointer to help avoid this in the future?

I do think this actually. 

https://github.com/llvm/llvm-project/pull/82411