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

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

@@ -0,0 +1,24 @@
+package foo
+
+import java.util.*
+
+fun <T> ArrayList<T>.findAll(predicate: (T) -> Boolean): ArrayList<T> {
+    val result = ArrayList<T>()
+    for (t in this) {
+        if (predicate(t)) result.add(t)
+    }
+    return result
+}
+
+
+fun box(): String {
+    val list: ArrayList<Int> = ArrayList<Int>()
+
+    list.add(2)
+    list.add(3)
+    list.add(5)
+
+
+    val m: ArrayList<Int> = list.findAll<Int>({ name: Int -> name < 4 })
+    return if (m.size == 2) "OK" else "fail"
+}