[ASTMatchers] Made isExpandedFromMacro Polymorphic

Made the isExpandedFromMacro matcher work on Stmt's, TypeLocs and Decls in line with the other macro expansion matchers.
Also tweaked it to take a `std::string` instead of a `StringRef`.
This prevents potential use-after-free bugs if the matcher is created with a string thats destroyed before the matcher finishes matching.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D90303