[compiler-rt] [compiler-rt] Don't explicitly ad-hoc code sign dylibs if using Apple's new linker (PR #88323)

[Julian Lettner via llvm-commits]

https://github.com/yln approved this pull request.

Change makes sense to me, thanks!

TIL: linker ad-hoc codesigns by default
```
man ld
...
     -adhoc_codesign
             Directs the linker to add an ad-hoc codesignature to the output file. The default for Apple Silicon binaries is to be ad-hoc codesigned.
```

https://github.com/llvm/llvm-project/pull/88323