Migrated several tests from blink to V8 repository.

test/webkit/dfg-convert-this-polymorphic-object-then-exit-on-string.js

Index: test/webkit/dfg-convert-this-polymorphic-object-then-exit-on-string.js
diff --git a/test/webkit/concat-while-having-a-bad-time.js b/test/webkit/dfg-convert-this-polymorphic-object-then-exit-on-string.js
similarity index 77%
copy from test/webkit/concat-while-having-a-bad-time.js
copy to test/webkit/dfg-convert-this-polymorphic-object-then-exit-on-string.js
index dfda1e08a0b36194b787a44ee12a9693acd8aeaf..14a4ecf24f4cd84af37bc45752b0b5647ab4d3bf 100644
--- a/test/webkit/concat-while-having-a-bad-time.js
+++ b/test/webkit/dfg-convert-this-polymorphic-object-then-exit-on-string.js
@@ -22,10 +22,24 @@
 // 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."
+"Tests that a convert_this optimized for the case where this is an object with polymorphic structure behaves correctly when you then pass a string."
 );
 
-Object.defineProperty(Array.prototype, 0, { writable: false });
-shouldBe("[42].concat()", "[42]");
+function foo() {
+    return this.x;
+}
 
+x = 42;
 
+String.prototype.x = 42;
+
+for (var i = 0; i < 1000; ++i) {
+    var me;
+    if (i < 150)
+        me = this;
+    else if (i < 950)
+        me = {x:42, y:62};
+    else
+        me = "hello";
+    shouldBe("foo.call(me)", "42");
+}