[Isolates] Avoid dereferencing Isolate::Current() to check oddball identities...

src/debug.cc

Index: src/debug.cc
===================================================================
--- src/debug.cc	(revision 5190)
+++ src/debug.cc	(working copy)
@@ -1057,7 +1057,8 @@
   }
 
   // Return whether the break point is triggered.
-  return *result == HEAP->true_value();
+  ASSERT(!result.is_null());
+  return (*result)->IsTrue();
 }
 
 
@@ -1333,7 +1334,8 @@
       // from the code object.
       Handle<Object> obj(
           HEAP->code_stubs()->SlowReverseLookup(*call_function_stub));
-      ASSERT(*obj != HEAP->undefined_value());
+      ASSERT(!obj.is_null());
+      ASSERT(!(*obj)->IsUndefined());
       ASSERT(obj->IsSmi());
       // Get the STUB key and extract major and minor key.
       uint32_t key = Smi::cast(*obj)->value();