Rollup merge of #138291 - jdonszelmann:optimize-attr, r=oli-obk

rewrite `optimize` attribute to use new attribute parsing infrastructure

r? ```@oli-obk```

I'm afraid we'll get quite a few of these PRs in the future. If we get a lot of trivial changes I'll start merging multiple into one PR. They should be easy to review :)

Waiting on #138165 first

compiler/rustc_parse/src/validate_attr.rs

@@ -291,6 +291,7 @@ fn emit_malformed_attribute(
             | sym::repr
             | sym::align
             | sym::deprecated
+            | sym::optimize
     ) {
         return;
     }