Use getPointerSizeInBits.

I introduced this bug in 198815. Thanks for Mark Lacey for noticing.
Unfortunately, I have no idea how to test this code.

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@198891 91177308-0d34-0410-b5e6-96231b3b80d8
Fix ast-dump-color.cpp test following r198883

The commit added a source location that used to be missing from the AST.

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@198892 91177308-0d34-0410-b5e6-96231b3b80d8