Fix pool shrinking with new allocations

Make BAllocThread.reduceSizeByDeallocating() call refill on the disregardPile and the newAllocations.
Otherwise, the pool might not be able to deallocate objects allocated but unused prior to a new target size being set.
This is normally not a big deal for pools that have any sort of activity, but the `ThreadedPoolTest.decreasingSizeMustNotDeallocateTlrClaimedObjects` test could end up in an infinite loop, and break the build.

src/main/java/stormpot/BAllocThread.java

@@ -154,6 +154,10 @@ private void increaseSizeByAllocating() {
   }
 
   private void reduceSizeByDeallocating(BSlot<T> slot) {
+    if (slot == null || !didAnythingLastIteration) {
+      disregardPile.refill();
+      newAllocations.refill();
+    }
     slot = slot == null ? live.poll() : slot;
     if (slot != null) {
       if (slot.isDead() || slot.live2dead()) {