Fix WinASan after moving wcslen interceptor to sanitizer_common

Do this by removing SANITIZER_INTERCEPT_WCSLEN and intercept wcslen
everywhere. Before this change, we were already intercepting wcslen on
Windows, but the interceptor was in asan, not sanitizer_common. After
this change, we stopped intercepting wcslen on Windows, which broke
asan_dll_thunk.c, which attempts to thunk to __asan_wcslen in the ASan
runtime.

llvm-svn: 306706