Deal with ASAN alloc-dealloc mismatch in class transformation code.

We change the unique_ptr deleters to use 'free' for these allocation
to match the allocations done by malloc.

This is temporary until we find a good way to communicate what
JvmtiEnv the buffers should be dealloced from.

This reverts commit ed81c1d3.

Test: SANITIZE_HOST=address test-art-host
Bug: 28322765
Change-Id: Ic60a11041d369c794fba6a70a6ff6d88bbbdd16b