[ADT] Attempt to fix GCC warning in IntrusiveRefCntPtrTest.

Our copy constructor doesn't explicitly invoke the base class's
constructor, and GCC is (rightly) concerned.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291023 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed