Update pointers in mourn queue during compaction.

Exchange topX and myX to keep topX alive while memory is compacted

smalltalksrc/VMMaker/SpurMemoryManager.class.st

@@ -857,8 +857,8 @@ SpurMemoryManager class >> initialize [
 	 created by popping emptied pages are kept on the ObjStackFreex list.
 	 ObjStackNextx must be the last field for swizzleObjStackAt:."
 	ObjStackPageSlots := 4092. "+ double header = 16k bytes per page in 32-bits"
-	ObjStackTopx := 0.
-	ObjStackMyx := 1.
+	ObjStackTopx := 1.
+	ObjStackMyx := 0.
 	ObjStackFreex := 2.
 	ObjStackNextx := 3.
 	ObjStackFixedSlots := 4.

smalltalksrc/VMMaker/SpurPlanningCompactor.class.st

@@ -890,11 +890,20 @@ SpurPlanningCompactor >> updatePointersInInitialImmobileObjects [
 SpurPlanningCompactor >> updatePointersInManagerHeapEntities [
 	"The special non-pointer objects containing pointers, which are the objStacks and the rememberedSet,
 	 must be updated manually since they will not be recognized as containing pointers in the normal sweep."
+
+	manager objStack: manager mournQueue do:
+		[:i :page| | mourner |
+		mourner := manager fetchPointer: i ofObject: page.
+		(manager isNonImmediate: mourner) ifTrue: [ | fwd |
+			fwd := manager fetchPointer: 0 ofObject: mourner.
+			manager storePointerUnchecked: i ofObject: page withValue: fwd ]].
+	
 	manager relocateObjStacksForPlanningCompactor.
 	(scavenger rememberedSetSize > 0
 	 and: [self isMobile: firstFieldOfRememberedSet]) ifTrue:
 		[firstFieldOfRememberedSet := manager fetchPointer: 0 ofObject: firstFieldOfRememberedSet].
-	self relocateObjectsInHeapEntity: manager rememberedSetObj from: 1 to: scavenger rememberedSetSize - 1
+	self relocateObjectsInHeapEntity: manager rememberedSetObj from: 1 to: scavenger rememberedSetSize - 1.
+	
 	"Note that we /must not/ set the rememberedSetObj here since it is a slot in the hiddenRootsObj
 	 and will be updated normally in updatePointersInInitialImmobileObjects.  So do not do
 	(self isMobile: manager rememberedSetObj) ifTrue: