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

js/js.translator/testData/box/callableReference/function/localAndTopLevelExtensions.kt

@@ -0,0 +1,22 @@
+package foo
+
+fun Int.sum0(other: Int): Int = this + other
+
+fun box(): String {
+    fun Int.sum1(other: Int): Int = this + other
+
+    val sum2 = fun Int.(other: Int): Int = this + other
+
+    var x = 10
+    x = x.sum0(5)
+    x = x.sum1(5)
+    x = x.sum2(5)
+
+    var y = 10
+    y = (Int::sum0)(y, 5)
+    y = (Int::sum1)(y, 5)
+    y = y.sum2(5)
+
+    var result:String = (if (x == y && x == 25) "OK" else "x=${x} y=${y}")
+    return result
+}