[Isolates] Merge (7083,7111] from bleeding_edge.

src/lithium-allocator.cc

Index: src/lithium-allocator.cc
diff --git a/src/lithium-allocator.cc b/src/lithium-allocator.cc
index 907932044c7d963b60fc2d908e8b8a4c07bcf776..4b49a983e6f208d8fee28d395ba5109950555bf0 100644
--- a/src/lithium-allocator.cc
+++ b/src/lithium-allocator.cc
@@ -1442,7 +1442,7 @@ void LAllocator::AllocateDoubleRegisters() {
 
 void LAllocator::AllocateRegisters() {
   ASSERT(mode_ != NONE);
-  reusable_slots_.Clear();
+  ASSERT(unhandled_live_ranges_.is_empty());
 
   for (int i = 0; i < live_ranges_.length(); ++i) {
     if (live_ranges_[i] != NULL) {
@@ -1454,6 +1454,7 @@ void LAllocator::AllocateRegisters() {
   SortUnhandled();
   ASSERT(UnhandledIsSorted());
 
+  ASSERT(reusable_slots_.is_empty());
   ASSERT(active_live_ranges_.is_empty());
   ASSERT(inactive_live_ranges_.is_empty());
 
@@ -1538,8 +1539,9 @@ void LAllocator::AllocateRegisters() {
     }
   }
 
-  active_live_ranges_.Clear();
-  inactive_live_ranges_.Clear();
+  reusable_slots_.Rewind(0);
+  active_live_ranges_.Rewind(0);
+  inactive_live_ranges_.Rewind(0);
 }