Smart completion includes object's from scope before searching for inheritors

#KT-6123 Fixed

idea/testData/completion/smart/Object.kt

@@ -0,0 +1,10 @@
+trait I
+
+object O : I
+
+fun foo(): I = <caret>
+
+// EXIST: { lookupString: "O", itemText: "O", tailText: " (<root>)" }
+// EXIST: foo
+// EXIST: object
+// NUMBER: 3