Fix code to mark block variables as const to actually work. Fix

isObjCObjectPointerType to work with qualified types.  Adjust test for 
changes.

If the SemaExpr changes are wrong or break existing code, feel free to 
delete the "ExprTy.addConst();" line and revert my changes to 
test/Sema/block-literal.c.

llvm-svn: 67489