[lld] [LLD][ELF] Add `-z execute-only-report` that checks PURECODE section flags (PR #128883)

[Fangrui Song via llvm-commits]

================
@@ -323,6 +324,7 @@ template <class ELFT> void Writer<ELFT>::run() {
   // finalizeSections does that.
   finalizeSections();
   checkExecuteOnly();
+  checkExecuteOnlyReport();
----------------
MaskRay wrote:

move into `checkExecuteOnly`

https://github.com/llvm/llvm-project/pull/128883