Generalize some operations on qualifiers. QualType::getQualifiers() and

::getCVRQualifiers() now look through array types, like all the other
standard queries.  Also, make a 'split' variant of getUnqualifiedType().



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@123751 91177308-0d34-0410-b5e6-96231b3b80d8