[llvm] [CodeGen] Mark LIFETIME_START and LIFETIME_END as mayLoad/mayStore (PR #211179)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm commented:

This probably isn't the right modeling. The meaning of "mayLoad" / "mayStore" is closer to has-memoperand. Now these will be treated as hasOrderedMemoryRef which is too strong 

https://github.com/llvm/llvm-project/pull/211179