Reland '[clang] Adding CharacteristicKind to PPCallbacks::InclusionDirective'

Reland '[clang] Adding CharacteristicKind to PPCallbacks::InclusionDirective'

This commit relands r331904.

Adding a SrcMgr::CharacteristicKind parameter to the InclusionDirective
in PPCallbacks, and updating calls to that function. This will be useful
in https://reviews.llvm.org/D43778 to determine which includes are
system
headers.

Differential Revision: https://reviews.llvm.org/D46614

llvm-svn: 332021