[clang] [clang-tools-extra] [llvm] `cp -r` replaces symlinks, update to `cp -R` (PR #201463)

[Aiden Grossman via cfe-commits]

https://github.com/boomanaiden154 commented:

I think we can drop the `-H` by default on all the `cp` invocations. If we're copying a symlink on the commandline, we should probably prefer `-L` to be consistent with the existing behavior.

`-H` is exactly equivalent to `-P` when none of the command line arguments are themselves symlinks, and it looks like all the platforms we're going to care about default to `-P`.

https://github.com/llvm/llvm-project/pull/201463