Completion: when Unit is expected do not prioritize by return type

Decide on completion order by other factors
Previously would prefer callable that return Unit if Unit is the expected type
    leading to strange completion order

 #KT-25588 Fixed

idea/idea-completion/testData/weighers/basic/DslMemberCalls.kt

@@ -11,10 +11,10 @@ fun main() {
     }
 }
 
+// ORDER: foo6
 // ORDER: foo2
 // ORDER: foo3
-// ORDER: foo6
 // ORDER: foo4
-// ORDER: foo1
 // ORDER: fooLocal
 // ORDER: foo5
+// ORDER: foo1