Compute the same hash for all NaN values.

test/mjsunit/regress/regress-3859.js

Index: test/mjsunit/regress/regress-3859.js
diff --git a/test/mjsunit/compiler/regress-451012.js b/test/mjsunit/regress/regress-3859.js
similarity index 63%
copy from test/mjsunit/compiler/regress-451012.js
copy to test/mjsunit/regress/regress-3859.js
index bffc8bc5bdfac32bb561a24153d00157b26ac3a5..3248ef14ac721ebfdedbd97923a90e7a83a0efe4 100644
--- a/test/mjsunit/compiler/regress-451012.js
+++ b/test/mjsunit/regress/regress-3859.js
@@ -2,11 +2,5 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-"use strict";
-function f() {
-  for (let v; v; ) {
-    let x;
-  }
-}
-
-f();
+assertEquals(1, new Set([NaN, NaN, NaN]).size);
+assertEquals(42, new Map([[NaN, 42]]).get(NaN));