Basic utility for rendering DataFlowValues

idea/testData/dataFlowValueRendering/complexIdentifierWithInitiallyNullableReceiver.kt

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