added new strict mode test

tests/baselines/reference/strictMode5.js

@@ -0,0 +1,46 @@
+//// [strictMode5.ts]
+function foo(...args) {
+    "use strict"
+}
+
+class A {
+    m() {
+        "use strict"
+
+        var v = () => {
+            return this.n();
+        };
+    }
+    n() {}
+}
+
+function bar(x: number = 10) {
+    "use strict"
+}
+
+//// [strictMode5.js]
+function foo() {
+    var args = [];
+    for (var _i = 0; _i < arguments.length; _i++) {
+        args[_i - 0] = arguments[_i];
+    }
+    "use strict";
+}
+var A = (function () {
+    function A() {
+    }
+    A.prototype.m = function () {
+        var _this = this;
+        "use strict";
+        var v = function () {
+            return _this.n();
+        };
+    };
+    A.prototype.n = function () {
+    };
+    return A;
+})();
+function bar(x) {
+    if (x === void 0) { x = 10; }
+    "use strict";
+}

tests/cases/compiler/strictMode5.ts

@@ -0,0 +1,18 @@
+function foo(...args) {
+    "use strict"
+}
+
+class A {
+    m() {
+        "use strict"
+
+        var v = () => {
+            return this.n();
+        };
+    }
+    n() {}
+}
+
+function bar(x: number = 10) {
+    "use strict"
+}