[CodeGen][test][NFC] Refactor ObjC attribute tests (#156519)
Some downstream work broke these tests because the attribute number
changed. Refactor these tests to be more resilient in the face of
changes like this
* `instrument-objc-method.m`
* `#1` was never checked, I think it was trying to check that
`__cyg_profile_func_enter` was not used, so I added
`--implicit-check-not="__cyg_profile_func_enter"`
* Use `[[#ATTR:]]` so the test doesn't fail if the number changes
* `address-safety-attr.mm`
* Check attributes in `Function Attrs:` so it's independent of the
attribute number