This patch started as an attempt to fix up the horrid naming

conventions. I then discovered a typo in the using declaration bit in
LookupSpecialMember. This led to discovering [namespace.udecl]p15, which
clang implements incorrectly. Thus I've added a comment and implemented
the code consistently with the rest of clang - that is incorrectly.

And because I don't want to include tests of something incorrect, I've
ripped the test out.

llvm-svn: 133784