FIR: fix type index computation during enhancement

1. in/out type parameters count;
2. star projections take up 1 space in the tree.

compiler/fir/analysis-tests/testData/resolve/kt41984.kt

@@ -21,11 +21,11 @@ open <!ABSTRACT_CLASS_MEMBER_NOT_IMPLEMENTED!>class B<!><V> : A<Any, V>() {
         return ""
     }
 
-    override fun takeInv(value: Inv<V>): String = ""
+    <!NOTHING_TO_OVERRIDE!>override<!> fun takeInv(value: Inv<V>): String = ""
 }
 
 fun test_1(b: B<Int>, x: Int, inv: Inv<Int>) {
     b.<!OVERLOAD_RESOLUTION_AMBIGUITY!>take<!>(x)
     b.<!NONE_APPLICABLE!>take<!>(null)
-    b.takeInv(inv)
+    b.<!OVERLOAD_RESOLUTION_AMBIGUITY!>takeInv<!>(inv)
 }