[builtins] add test for Array.shift on holey double array

Adding the missing test for https://chromium-review.googlesource.com/c/603717.

Bug: chromium:752722
Change-Id: I8a4ca161b691532e481ebe9f7d05c306beb4c90a
Reviewed-on: https://chromium-review.googlesource.com/604792Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47212}

test/mjsunit/array-shift5.js

@@ -34,6 +34,21 @@
   test();
 })();
 
+(function() {
+  function doShift(a) { return a.shift(); }
+
+  function test() {
+    var a = [,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16.1];
+    assertEquals(undefined, doShift(a));
+    assertEquals([1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16.1], a);
+  }
+
+  test();
+  test();
+  %OptimizeFunctionOnNextCall(doShift);
+  test();
+})();
+
 (function() {
   function doShift(a) { return a.shift(); }