[lld] [LLD][ELF][AArch64] Mark .plt and .iplt with PURECODE flag (PR #134798)

[Csanád Hajdú via llvm-commits]

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@@ -14,6 +14,7 @@
 // CHECKDSO:     Name: .plt
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Il-Capitano wrote:

Thinking about this a bit more, I think that it is redundant to test if `.plt` ends up in an execute-only LOAD segment, because the `.plt` we're testing here is a regular output section, not the synthetic input section. There are already tests for making sure execute-only sections end up in execute-only LOAD segments, e.g. [lld/test/ELF/aarch64-execute-only-mixed.s](https://github.com/llvm/llvm-project/blob/main/lld/test/ELF/aarch64-execute-only-mixed.s).

https://github.com/llvm/llvm-project/pull/134798