sre: use malloc internally instead of our GC memory alloc routines

from_cpython/Modules/_sre.c

@@ -257,7 +257,9 @@ static void
 data_stack_dealloc(SRE_STATE* state)
 {
     if (state->data_stack) {
-        PyMem_FREE(state->data_stack);
+        // Pyston change: use malloc
+        // PyMem_FREE(state->data_stack);
+        free(state->data_stack);
         state->data_stack = NULL;
     }
     state->data_stack_size = state->data_stack_base = 0;
@@ -273,7 +275,9 @@ data_stack_grow(SRE_STATE* state, Py_ssize_t size)
         void* stack;
         cursize = minsize+minsize/4+1024;
         TRACE(("allocate/grow stack %" PY_FORMAT_SIZE_T "d\n", cursize));
-        stack = PyMem_REALLOC(state->data_stack, cursize);
+        // Pyston change: use malloc
+        // stack = PyMem_REALLOC(state->data_stack, cursize);
+        stack = realloc(state->data_stack, cursize);
         if (!stack) {
             data_stack_dealloc(state);
             return SRE_ERROR_MEMORY;