- Remove PTHManager.cpp.  Move all of its functions to PTHLexer.cpp since some of the internal methods are used by PTHLexer (their implementations are intertwined.)  This enables some important inlining opportunities at -O3.

- Don't construct an std::vector<Token> prior to feeding PTH tokens to the Preprocessor.  Stream them off the PTH file directly.

llvm-svn: 60447