The disabled code was too late to make eclair, and there were some
bugs on x86, now fixed.

Let's get this into master for some burn-in.
diff --git a/vm/alloc/MarkSweep.c b/vm/alloc/MarkSweep.c
index fda4e6d..a3279d8 100644
--- a/vm/alloc/MarkSweep.c
+++ b/vm/alloc/MarkSweep.c
@@ -403,7 +403,7 @@
 static void scanInstanceFields(const DataObject *obj, ClassObject *clazz,
         GcMarkContext *ctx)
 {
-    if (false && clazz->refOffsets != CLASS_WALK_SUPER) {
+    if (clazz->refOffsets != CLASS_WALK_SUPER) {
         unsigned int refOffsets = clazz->refOffsets;
         while (refOffsets != 0) {
             const int rshift = CLZ(refOffsets);