[CMake][compiler-rt] Use copying instead of symlinking for LSE builtins on non-Unix-likes

As reported in D93278 post-review symlinking requires privilege escalation on Windows.
Copying is functionally same, so fallback to it for systems that aren't Unix-like.
This is similar to the solution in AddLLVM.cmake.

Reviewed By: ikudrin

Differential Revision: https://reviews.llvm.org/D98111