Have clang_getSpellingLocation() use the same logic as DiagnosticRenderer for plowing through macros.

This fixes a subtle bug reported in <rdar://problem/12584554> where a double-nested
macro could lead to an incorrect fixit location with live issues.

This fix also uncovers a bunch of subtle bugs in our indexer test cases which
are now fixed (mostly around source ranges for attributes).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@170468 91177308-0d34-0410-b5e6-96231b3b80d8