[clang][CodeGen] Break up TargetInfo.cpp [1/8]

`CCState` is a helper class originally used by the x86 implementation
but has since been abused by other implementations.
Remove this dependency by implementing customized versions of the class
for implementations that need such functionality.

Reviewed By: efriedma, MaskRay

Differential Revision: https://reviews.llvm.org/D148089