Handle ambiguities between expressions and type-ids that occur inside parentheses, e.g.:

sizeof(int()) -> "int()" is type-id
sizeof(int()+1) -> "int()+1" is expression.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@57131 91177308-0d34-0410-b5e6-96231b3b80d8