Ensure canonical type is actually canonical.

Ensure canonical type is actually canonical.

ASTContext::applyObjCProtocolQualifiers will return a canonical type when given
a canonical type and an array of canonical protocols.  If the protocols are not
canonical then the returned type is also not canonical.  Since a canonical type is needed, canonicalize the returned type before using it.  This later prevents
a type from having a non-canonical canonical type.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@341013 91177308-0d34-0410-b5e6-96231b3b80d8