Unuse labels when bailing out of StubCompiler methods....

src/x64/stub-cache-x64.cc

Index: src/x64/stub-cache-x64.cc
===================================================================
--- src/x64/stub-cache-x64.cc	(revision 5507)
+++ src/x64/stub-cache-x64.cc	(working copy)
@@ -1701,7 +1701,10 @@
   Failure* failure = Failure::InternalError();
   bool success = GenerateLoadCallback(object, holder, rax, rcx, rbx, rdx, rdi,
                                       callback, name, &miss, &failure);
-  if (!success) return failure;
+  if (!success) {
+    miss.Unuse();
+    return failure;
+  }
 
   __ bind(&miss);
   GenerateLoadMiss(masm(), Code::LOAD_IC);
@@ -1757,7 +1760,10 @@
                                              name,
                                              rdx,
                                              &miss);
-    if (cell->IsFailure()) return cell;
+    if (cell->IsFailure()) {
+      miss.Unuse();
+      return cell;
+    }
   }
 
   // Return undefined if maps of the full prototype chain are still the
@@ -1895,7 +1901,10 @@
   Failure* failure = Failure::InternalError();
   bool success = GenerateLoadCallback(receiver, holder, rdx, rax, rbx, rcx, rdi,
                                       callback, name, &miss, &failure);
-  if (!success) return failure;
+  if (!success) {
+    miss.Unuse();
+    return failure;
+  }
 
   __ bind(&miss);
   __ DecrementCounter(&Counters::keyed_load_callback, 1);