Several PPCallbacks take an SourceLocation + IdentifierInfo, rather

Several PPCallbacks take an SourceLocation + IdentifierInfo, rather
than a Token that holds the same information all in one easy-to-use
package.  There's no technical reason to prefer the former -- the
information comes from a Token originally -- and it's clumsier to use,
so I've changed the code to use tokens everywhere.

Approved by clattner

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@119845 91177308-0d34-0410-b5e6-96231b3b80d8