[ASTPrinter] 'SEL' isn't a ObjCObjectPointer, so we don't need to handle it in TypePrinter::printObjCObjectPointerBefore.

Suggested by Jordan.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@203124 91177308-0d34-0410-b5e6-96231b3b80d8