My attempt at fixing the leak reported by the valgrind buildbots. Valgrind will

My attempt at fixing the leak reported by the valgrind buildbots. Valgrind will
still report leaks, but they're spurious now. Valgrind cannot peer into
std::vector objects--or any dynamic array, for that matter--because it doesn't
know how big the array is.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132174 91177308-0d34-0410-b5e6-96231b3b80d8