Make DescriptorArray::IsMoreGeneralThan() and DescriptorArray::Merge() compatible again.

test/mjsunit/regress/regress-365172-1.js

Index: test/mjsunit/regress/regress-365172-1.js
diff --git a/test/mjsunit/harmony/regress/regress-crbug-346141.js b/test/mjsunit/regress/regress-365172-1.js
similarity index 51%
copy from test/mjsunit/harmony/regress/regress-crbug-346141.js
copy to test/mjsunit/regress/regress-365172-1.js
index 798b7704ec2cc0eb928966fdfe9f979d0fe51f94..ea68285ea0343b2d49935763418e43ef7f329e51 100644
--- a/test/mjsunit/harmony/regress/regress-crbug-346141.js
+++ b/test/mjsunit/regress/regress-365172-1.js
@@ -2,10 +2,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Flags: --harmony-symbols
+// Flags: --track-field-types
 
-var s = Symbol()
-var o = {}
-o[s] = 2
-o[""] = 3
-Object.getOwnPropertySymbols(o)
+var b1 = {d: 1}; var b2 = {d: 2};
+var f1 = {x: 1}; var f2 = {x: 2};
+f1.b = b1;
+f2.x = {};
+b2.d = 4.2;
+f2.b = b2;
+var x = f1.x;