Add more information to JSON AST dumping of source locations.

This adds information about the offset within the source file to the given source location as well as information about the include file a location is from. These pieces of information allow for more efficient post-processing of JSON AST dumps.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@374921 91177308-0d34-0410-b5e6-96231b3b80d8
26 files changed