[test] Test expectations in cctest should use CHECK and not DCHECK.

test/cctest/test-unboxed-doubles.cc

Index: test/cctest/test-unboxed-doubles.cc
diff --git a/test/cctest/test-unboxed-doubles.cc b/test/cctest/test-unboxed-doubles.cc
index 09c185c84beaf454308e8786ccdb8ee1fe5040c6..4bd1fc3944abbc59baa3841e4cc9a2992e91c35c 100644
--- a/test/cctest/test-unboxed-doubles.cc
+++ b/test/cctest/test-unboxed-doubles.cc
@@ -68,7 +68,7 @@ static double GetDoubleFieldValue(JSObject* obj, FieldIndex field_index) {
     return obj->RawFastDoublePropertyAt(field_index);
   } else {
     Object* value = obj->RawFastPropertyAt(field_index);
-    DCHECK(value->IsMutableHeapNumber());
+    CHECK(value->IsMutableHeapNumber());
     return HeapNumber::cast(value)->value();
   }
 }