sanitizer_common: add test that calls wcslen

sanitizer_common: add test that calls wcslen

This is a very simple test that calls wsclen. There are currently no other HWASan tests that call wsclen, which is why the wcslen interceptor issue (triggered by https://reviews.llvm.org/D150708 and fixed in https://reviews.llvm.org/D150909) was only detected by stage2/hwasan check on the buildbots. With this test, the issue would have been caught by stage1 check-sanitizer, with a more obvious diagnosis.

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D151000