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

js/js.translator/testData/box/closure/recursiveExtFunction.kt

@@ -0,0 +1,35 @@
+package foo
+
+fun Int.foo(a: Int): Int {
+    if (a == 0) {
+        return this.foo(4) + foo(7) + this
+    }
+
+    return a
+}
+
+fun box(): String {
+    assertEquals(34, 23.foo(0))
+
+    fun Int.bar(a: Int): Int {
+        if (a == 0) {
+            return this.bar(12) + bar(4) + this
+        }
+
+        return a
+    }
+    assertEquals(19, 3.bar(0))
+
+    fun f() = 11
+    val v = 3
+    fun Int.baz(a: Int): Int {
+        if (a == 0) {
+            return this.baz(v) + baz(f()) + this
+        }
+
+        return a
+    }
+    assertEquals(21, 7.baz(0))
+
+    return "OK"
+}