Implement proper support for generating code for compound literals in

C++, which means:
  - binding the temporary as needed in Sema, so that we generate the
  appropriate call to the destructor, and
  - emitting the compound literal into the appropriate location for
  the aggregate, rather than trying to emit it as a temporary and
  memcpy() it.

Fixes PR10138 / <rdar://problem/9615901>.

llvm-svn: 133235