Fix invalid ASSERT() in HasStableMapValue().

R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/267363002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21183 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/hydrogen-instructions.h

@@ -3617,7 +3617,7 @@ class HConstant V8_FINAL : public HTemplateInstruction<0> {
     return Unique<Map>::cast(GetUnique());
   }
   bool HasStableMapValue() const {
-    ASSERT(HasMapValue());
+    ASSERT(HasMapValue() || !has_stable_map_value_);
     return has_stable_map_value_;
   }