[runtimes] Fix link order of system librarires on Apple platforms (#66940)

On Apple platforms, we always support the -nostdlib++ flag. Hence, it is
not necessary to manually link against system libraries. In fact, doing
so causes us to link against libSystem explicitly, which messes up with
the order of libraries we should use. Indeed:

   Before patch, using the system unwinder (LIBCXXABI_USE_LLVM_UNWINDER = OFF)
   ===========================================================================
   $ otool -L lib/{libc++.1.dylib,libc++abi.1.dylib,libunwind.1.dylib}
   lib/libc++.1.dylib:
         @rpath/libc++.1.dylib
         /usr/lib/libSystem.B.dylib
         @rpath/libc++abi.1.dylib
   lib/libc++abi.1.dylib:
         @rpath/libc++abi.1.dylib
         /usr/lib/libSystem.B.dylib
   lib/libunwind.1.dylib:
         @rpath/libunwind.1.dylib
         /usr/lib/libSystem.B.dylib

   After patch, using the system unwinder (LIBCXXABI_USE_LLVM_UNWINDER = OFF)
   ==================================...