[compiler-rt] [compiler-rt][asan] Add wcscpy/wcsncpy; enable wcscat/wcsncat on Windows (PR #160493)

[Thurston Dang via llvm-commits]

thurstond wrote:

Please use a public email address per https://llvm.org/docs/DeveloperPolicy.html#email-addresses:

> The LLVM project uses email to communicate to contributors outside of the GitHub platform about their past contributions. Primarily, our buildbot infrastructure uses emails to contact contributors about build and test failures.
>
> Therefore, the LLVM community requires contributors to have a public email address associated with their GitHub commits, so please ensure that “Keep my email addresses private” is disabled in your account settings. There are many free email forwarding services available if you wish to keep your identity private.

https://github.com/llvm/llvm-project/pull/160493