Adding test

Author: ahejlsberg

tests/baselines/reference/restElementWithNullInitializer.errors.txt

@@ -0,0 +1,8 @@
+tests/cases/conformance/es6/destructuring/restElementWithNullInitializer.ts(1,14): error TS2461: Type 'null' is not an array type.
+
+
+==== tests/cases/conformance/es6/destructuring/restElementWithNullInitializer.ts (1 errors) ====
+    function foo([...r] = null) { }
+                 ~~~~~~
+!!! error TS2461: Type 'null' is not an array type.
+    

tests/baselines/reference/restElementWithNullInitializer.js

@@ -0,0 +1,6 @@
+//// [restElementWithNullInitializer.ts]
+function foo([...r] = null) { }
+
+
+//// [restElementWithNullInitializer.js]
+function foo(_a) { }

tests/cases/conformance/es6/destructuring/restElementWithNullInitializer.ts

@@ -0,0 +1 @@
+function foo([...r] = null) { }