[Xcode 15] Check if we still need to force the classic/ld64 linker

[rolfbjarne]

As description says.

Ref:

• 4669ae9 (#18440)
• [net8.0-xcode15] [tools] Improve enforcement of the classic linker. #18719

[filipnavara]

JFYI dotnet/runtime#97745 (comment)

[rolfbjarne]

Fixed.