[lld] [LLD][ELF] Don't spill to same memory region (PR #129795)

[Peter Smith via llvm-commits]

https://github.com/smithp35 commented:

Thanks for the fix. I expect that was a fun one to track down.

I got a little surprised by the removal of `sec->parent == &outCmd` as these came first and it seemed like these might help rather than hinder. IIUC these are no longer necessary, rather than being required (tests still pass if I remove them).

https://github.com/llvm/llvm-project/pull/129795