Sema: Implement DR244

Summary:
Naming the destructor using a typedef-name for the class-name is
well-formed.

This fixes PR19620.

Reviewers: rsmith, doug.gregor

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D3583

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@209319 91177308-0d34-0410-b5e6-96231b3b80d8