[heap] Use the thread-safe free modes also for RemoveRange in SlotSet.

test/unittests/heap/slot-set-unittest.cc

Index: test/unittests/heap/slot-set-unittest.cc
diff --git a/test/unittests/heap/slot-set-unittest.cc b/test/unittests/heap/slot-set-unittest.cc
index 65b79253105be64e8d02ba094f6c5b379dfae115..d24ed1322b4042851cdde1da64611a340b94fc4b 100644
--- a/test/unittests/heap/slot-set-unittest.cc
+++ b/test/unittests/heap/slot-set-unittest.cc
@@ -104,7 +104,7 @@ void CheckRemoveRangeOn(uint32_t start, uint32_t end) {
   for (uint32_t i = first; i <= last; i += kPointerSize) {
     set.Insert(i);
   }
-  set.RemoveRange(start, end);
+  set.RemoveRange(start, end, SlotSet::FREE_EMPTY_BUCKETS);
   if (first != start) {
     EXPECT_TRUE(set.Lookup(first));
   }
@@ -135,7 +135,7 @@ TEST(SlotSet, RemoveRange) {
   SlotSet set;
   set.SetPageStart(0);
   set.Insert(Page::kPageSize / 2);
-  set.RemoveRange(0, Page::kPageSize);
+  set.RemoveRange(0, Page::kPageSize, SlotSet::FREE_EMPTY_BUCKETS);
   for (uint32_t i = 0; i < Page::kPageSize; i += kPointerSize) {
     EXPECT_FALSE(set.Lookup(i));
   }