Add Array#copyWithin test

test/built-ins/Array/prototype/copyWithin/length-near-integer-limit.js

@@ -0,0 +1,43 @@
+// Copyright (C) 2020 Alexey Shvayka. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.copywithin
+description: >
+  Elements are copied and deleted in an array-like object
+  whose "length" property is near the integer limit.
+info: |
+  Array.prototype.copyWithin ( target, start [ , end ] )
+
+  1. Let O be ? ToObject(this value).
+  2. Let len be ? LengthOfArrayLike(O).
+  [...]
+  9. Let count be min(final - from, len - to).
+  [...]
+  12. Repeat, while count > 0
+    [...]
+    d. If fromPresent is true, then
+      i. Let fromVal be ? Get(O, fromKey).
+      ii. Perform ? Set(O, toKey, fromVal, true).
+    e. Else,
+      i. Assert: fromPresent is false.
+      ii. Perform ? DeletePropertyOrThrow(O, toKey).
+    [...]
+---*/
+
+var startIndex = Number.MAX_SAFE_INTEGER - 3;
+var arrayLike = {
+  0: 0,
+  1: 1,
+  2: 2,
+  length: Number.MAX_SAFE_INTEGER,
+};
+
+arrayLike[startIndex] = -3;
+arrayLike[startIndex + 2] = -1;
+
+Array.prototype.copyWithin.call(arrayLike, 0, startIndex, startIndex + 3);
+
+assert.sameValue(arrayLike[0], -3);
+assert.sameValue(1 in arrayLike, false);
+assert.sameValue(arrayLike[2], -1);