now that this handles the release / retain calls.
Adds a regression test for that bug (which is a compile-time
regression) and for the last two changes to the IntrusiveRefCntPtr,
especially tests for the memory leak due to copy construction of the
ref-counted object and ensuring that the traits are used for release /
retain calls.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149411 91177308-0d34-0410-b5e6-96231b3b80d8
