Migrated several tests from blink to V8 repository.

test/webkit/dfg-cfa-merge-with-dead-use-at-tail.js

Index: test/webkit/dfg-cfa-merge-with-dead-use-at-tail.js
diff --git a/test/webkit/concat-while-having-a-bad-time.js b/test/webkit/dfg-cfa-merge-with-dead-use-at-tail.js
similarity index 77%
copy from test/webkit/concat-while-having-a-bad-time.js
copy to test/webkit/dfg-cfa-merge-with-dead-use-at-tail.js
index dfda1e08a0b36194b787a44ee12a9693acd8aeaf..ab9f2a5634bbcc2d180edd0a9341ec95f7444ad7 100644
--- a/test/webkit/concat-while-having-a-bad-time.js
+++ b/test/webkit/dfg-cfa-merge-with-dead-use-at-tail.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 dead use of a variable at the tail of a basic block doesn't confuse the CFA into believing that the variable being used is dead as well."
 );
 
-Object.defineProperty(Array.prototype, 0, { writable: false });
-shouldBe("[42].concat()", "[42]");
-
+function foo(p, q, v) {
+    var x, y;
+    if (p)
+        x = 0;
+    else {
+        if (q)
+            x = v;
+        else
+            x = 0;
+        y = x;
+    }
+    if (x)
+        return 42;
+    return 0;
+}
 
+for (var i = 0; i < 200; ++i)
+    shouldBe("foo(false, true, 5)", "42");