JS: create new common directory for all generated tests, migrate several tests there

js/js.translator/testData/box/extensionFunction/extensionInsideFunctionLiteral.kt

@@ -0,0 +1,22 @@
+package foo
+
+class M() {
+    var m = 0
+
+    fun eval() {
+        var d = {
+            var c = fun Int.(): Int = this + 3
+            m += 3.c()
+        }
+        d();
+    }
+}
+
+fun box(): String {
+    var a = M()
+    if (a.m != 0) return "fail1: ${a.m}";
+    a.eval()
+    if (a.m != 6) return "fail2: ${a.m}";
+
+    return "OK";
+}