Add String.prototype.replace test

test/built-ins/String/prototype/replace/cstm-replace-is-null.js

@@ -0,0 +1,34 @@
+// Copyright (C) 2020 Alexey Shvayka. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-string.prototype.replace
+description: >
+  If searchValue's Symbol.replace property is null, no error is thrown.
+info: |
+  String.prototype.replace ( searchValue, replaceValue )
+
+  [...]
+  2. If searchValue is neither undefined nor null, then
+    a. Let replacer be ? GetMethod(searchValue, @@replace).
+    b. If replacer is not undefined, then
+      [...]
+  [...]
+  12. Return newString.
+
+  GetMethod ( V, P )
+
+  [...]
+  2. Let func be ? GetV(V, P).
+  3. If func is either undefined or null, return undefined.
+features: [Symbol.replace]
+---*/
+
+var searchValue = {};
+searchValue[Symbol.replace] = null;
+searchValue.toString = function() { return "3"; };
+searchValue.valueOf = function() { throw new Test262Error("should not be called"); };
+
+var replacer = function() { return "<foo>"; };
+assert.sameValue("ab3c".replace(searchValue, replacer), "ab<foo>c");
+assert.sameValue("ab3c".replace(searchValue, "<foo>"), "ab<foo>c");