Basic utility for rendering DataFlowValues

idea/testData/dataFlowValueRendering/complexIdentifierWithReceiver.kt

@@ -0,0 +1,9 @@
+fun C.outer(a: Any?) {
+    if (this.x is String) {
+        <caret>null
+    }
+}
+
+class C {
+    val x: Any? = null
+}