[clang][diagnostics] Add '-Wundef-prefix' warning option

Summary:
Add an `-Wundef-prefix=<arg1>,<arg2>...` option, which is similar to `-Wundef`, but only give warnings for undefined macros with the given prefixes.

Reviewers: ributzka, steven_wu, cishida, bruno, arphaman, rsmith

Reviewed By: ributzka, arphaman

Subscribers: riccibruno, dexonsmith, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D80751

This patch was authored by Zixu Wang <zixu_wang@apple.com>