Data Inflow: Support delegated assignments

#KT-19089 Fixed

idea/testData/slicer/inflow/settersViaDelegateForSimpleRef.kt

@@ -0,0 +1,26 @@
+// FLOW: IN
+
+class Delegate {
+    private var _value: String = ""
+    operator fun getValue(thisRef: Any?, property: KProperty<*>) = _value
+    operator fun setValue(thisRef: Any?, property: KProperty<*>, value: String) {
+        _value = value
+    }
+}
+
+class AClass(name1: String){
+    var name by Delegate()
+    init {
+        name = name1
+    }
+
+    fun uses(){
+        name = "bye"
+        println("Now my name is '$<caret>name'")
+    }
+}
+
+fun main(args: Array<String>) {
+    val a = AClass("hello")
+    println("My name is '${a.name}'")
+}