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

js/js.translator/testData/box/delegateProperty/delegateByExtensionProperty.kt

@@ -0,0 +1,41 @@
+package foo
+
+import kotlin.reflect.KProperty
+
+class State(var realValue: Int)
+
+fun format(event: String, property: String, value: Int): String
+    = "${event}: ${property} = ${value}; "
+
+object LoggerDelegate {
+    var log = ""
+
+    operator fun getValue(state: State, desc: KProperty<*>): Int {
+        log += format("get", desc.name, state.realValue)
+        return state.realValue
+    }
+
+    operator fun setValue(state: State, desc: KProperty<*>, value: Int) {
+        log += format("set", desc.name, value)
+        state.realValue = value
+    }
+}
+
+var State.value by LoggerDelegate
+
+fun box(): String {
+    val state = State(1)
+    var expectedLog = ""
+
+    assertEquals(1, state.value)
+    expectedLog += format("get", "value", 1)
+
+    state.value = 3
+    expectedLog += format("set", "value", 3)
+
+    assertEquals(3, state.value)
+    expectedLog += format("get", "value", 3)
+
+    assertEquals(expectedLog, LoggerDelegate.log)
+    return "OK"
+}