Migrate more tests from blink repository.

test/webkit/fast/js/array-tostring-ignore-separator.js

Index: test/webkit/fast/js/array-tostring-ignore-separator.js
diff --git a/test/webkit/concat-while-having-a-bad-time.js b/test/webkit/fast/js/array-tostring-ignore-separator.js
similarity index 83%
copy from test/webkit/concat-while-having-a-bad-time.js
copy to test/webkit/fast/js/array-tostring-ignore-separator.js
index dfda1e08a0b36194b787a44ee12a9693acd8aeaf..3390eb2e81a7481a909614a5eb3b71c1004fec35 100644
--- a/test/webkit/concat-while-having-a-bad-time.js
+++ b/test/webkit/fast/js/array-tostring-ignore-separator.js
@@ -22,10 +22,11 @@
 // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 description(
-"Tests the behavior of Array.prototype.concat while the array is having a bad time due to one of the elements we are concatenating."
+'This test checks for regressions against <a href="https://bugs.webkit.org/show_bug.cgi?id=6261">6261:Do not use a separator argument when doing toString/toLocalString.</a>'
 );
 
-Object.defineProperty(Array.prototype, 0, { writable: false });
-shouldBe("[42].concat()", "[42]");
-
-
+var a = new Array;
+a[0] = 5;
+a[1] = 3;
+//Shouldn't use argument for toString
+shouldBe("a.toString('!')", "'5,3'");