don't use toggle, since our assert ensures not free only in debug builds. ...

don't use toggle, since our assert ensures not free only in debug builds.  also, more valgrind error disabling for access to the GCAllocation data

src/gc/heap.cpp

@@ -614,7 +614,7 @@ void SmallArena::_free(GCAllocation* alloc, Block* b) {
     int atom_idx = offset / ATOM_SIZE;
 
     assert(!b->isfree.isSet(atom_idx));
-    b->isfree.toggle(atom_idx);
+    b->isfree.set(atom_idx);
 
 #ifndef NVALGRIND
 // VALGRIND_MEMPOOL_FREE(b, ptr);
@@ -625,8 +625,22 @@ void _doFree(GCAllocation* al) {
     if (VERBOSITY() >= 2)
         printf("Freeing %p\n", al->user_data);
 
-    if (al->kind_id == GCKind::PYTHON) {
+#ifndef NVALGRIND
+    VALGRIND_DISABLE_ERROR_REPORTING;
+#endif
+    GCKind alloc_kind = al->kind_id;
+#ifndef NVALGRIND
+    VALGRIND_ENABLE_ERROR_REPORTING;
+#endif
+
+    if (alloc_kind == GCKind::PYTHON) {
+#ifndef NVALGRIND
+        VALGRIND_DISABLE_ERROR_REPORTING;
+#endif
         Box* b = (Box*)al->user_data;
+#ifndef NVALGRIND
+        VALGRIND_ENABLE_ERROR_REPORTING;
+#endif
 
         ASSERT(b->cls->tp_dealloc == NULL, "%s", getTypeName(b));
         if (b->cls->simple_destructor)