Add positioning strategy for diagnostics on illegal fake overrides

"funcitonTypes.kt" test data file was changed because now that there is a
positioning strategy, it takes the liberty of filtering out those diagnostics
that were reported on syntactically invalid elements

compiler/testData/diagnostics/tests/incompleteCode/diagnosticWithSyntaxError/funcitonTypes.kt

@@ -1 +1 @@
-class <!ABSTRACT_MEMBER_NOT_IMPLEMENTED!>A<!> : (categoryName: <!SYNTAX!><!>) <!SYNTAX!>{<!SYNTAX!><!><!>
+class A : (categoryName: <!SYNTAX!><!>) <!SYNTAX!>{<!SYNTAX!><!><!>