Improving source type info for typeof nodes.

Hello.

Please find attached a patch for improving the type source info available for TypeOfExprType and TypeOfType nodes.

The augmented TypeOf(Expr)TypeLoc nodes provide info about:
   - the location of the typeof keyword;
   - the locations of the left&right parentheses (may be invalid);
   - the source range for the whole typeof construct;
   - source type info for the underlying type (for TypeOfType nodes).

The patch passes all clang tests.

Cheers,
Enea Zaffanella.

Typeof-TypeLoc.patch (11.9 KB)

Looks great. Committed as r93344, thanks!

John.