[NI] Remove direcion calculator from variable fixation

Force constraint system completer to always fix variable with unknown position.
This makes inferred type for in parameters less specific, but OI infers to
subtype in such cases, so NI won't infer to less specific types than before.

compiler/testData/diagnostics/tests/inference/completion/basic.kt

@@ -57,14 +57,13 @@ fun test7(cls: Cls) {
 }
 
 fun test8(cls: Cls) {
-    // TODO
-    <!IMPLICIT_NOTHING_AS_TYPE_PARAMETER, TYPE_MISMATCH!>id<!>(
+    id(
         <!DEBUG_INFO_EXPRESSION_TYPE("Inv<in Cls>")!>wrapIn(cls)<!>
     )
 }
 
 fun test9(cls: Cls) {
     id(
-        <!DEBUG_INFO_EXPRESSION_TYPE("InB<Bound>")!>InB(cls)<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("InB<Cls>")!>InB(cls)<!>
     )
 }