[libclang 2/8] Add support for ObjCTypeParam

Summary:
This patch adds support to the libclang API for identifying ObjCTypeParams in CXTypes.

This patch depends on D49063 since both patches add new values to CXTypeKind.

Reviewers: yvvan, jbcoe

Reviewed By: yvvan

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D49066

llvm-svn: 338807