FIR: fix of super.methodOfAny resolve in case of one supertype

compiler/testData/diagnostics/tests/thisAndSuper/unqualifiedSuper/withMethodOfAnyOverridenInInterface.fir.kt

@@ -1,8 +0,0 @@
-interface IWithToString {
-    override fun toString(): String
-}
-
-class A : IWithToString {
-    // Should be Any#toString(), even though IWithToString defines an abstract toString.
-    override fun toString(): String = super.<!ABSTRACT_SUPER_CALL!>toString<!>()
-}

compiler/testData/diagnostics/tests/thisAndSuper/unqualifiedSuper/withMethodOfAnyOverridenInInterface.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 interface IWithToString {
     override fun toString(): String
 }