[clang][compiler-rt][atomics] Add `__c11_atomic_fetch_nand` builtin and...

[clang][compiler-rt][atomics] Add `__c11_atomic_fetch_nand` builtin and support `__atomic_fetch_nand` libcall

Add `__c11_atomic_fetch_nand` builtin to language extensions and support `__atomic_fetch_nand` libcall in compiler-rt.

Reviewed By: theraven

Differential Revision: https://reviews.llvm.org/D112400