llvm_15: reenable libclang_rt.profile-....a build on musl

[yu-re-ka]

This was most likely lost because of a bad merge

Note how a few lines below it is already disabled for useLLVM || bareMetal, so they get the COMPILER_RT_BUILD_PROFILE=OFF flag twice.

Change for LLVM 14 was in #191372

Description of changes

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 23.05 Release Notes (or backporting 22.11 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

[rrbutani]

ahh, sorry, I bungled this in rrbutani@8c4b8b5; thanks for the fix!

---

Definitely doesn't need to be part of this PR or anything but it'd be great to have a regression test for this!

I'm not sure the best way to go about adding one though; @yu-re-ka do you generally notice errors like this because those compiler-rt files are missing or does this manifest as link errors when you try to use -fprofile-instr-generate or something similar?

Edit: nvm, just saw in your original PR that this gets tested as part of the pkgsMusl.firefox build.

[yu-re-ka]

I notice this when I build pkgsMusl.firefox with PGO enabled