Implement a little bit of cleanup and a lot more of the base work

Implement a little bit of cleanup and a lot more of the base work
behind implicit moves. We now correctly identify move constructors and
assignment operators and update bits on the record correctly. Generation
of implicit moves (declarations or definitions) is not yet supported.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@132080 91177308-0d34-0410-b5e6-96231b3b80d8