Don't test OOM handling of debugallocator

This may fix issue #969.

When testing OOM handling we set up sys allocator that fails memory
allocation. But debugallocator itself allocates some internal metadata
memory via malloc and crashes if those allocations fail. So
occasionally this test failed when debugallocator's internal malloc
ended up causing sys allocator.

So instead of failing tests from time to time, we drop it for debug
allocator. It's OOM handling is already crashy anyways.
1 file changed