Use information about receivers in completion

- Found few problems during resolving a single functon; disabled
assertions and marked them with TODO
- Add simple completion tests to simplify development

idea/idea-completion/testData/basic/common/primitiveCompletion/implicitReceiverCompletion.kt

@@ -0,0 +1,24 @@
+class A {
+    fun aa() {}
+    val aaa = 10
+}
+
+fun A.run(action: A.() -> Unit) {}
+
+fun test(a: A) {
+    a.run {
+
+        <caret>
+
+        // remove this
+        Unit
+    }
+}
+
+// this does not work for some reason
+//fun A.test() {
+//}
+
+// EXIST: aa
+// EXIST: aaa
+// EXIST: run