[FIR] Fix removeAtInt test

compiler/testData/diagnostics/tests/j+k/collectionOverrides/removeAtInt.kt

@@ -1,4 +1,3 @@
-// FIR_IDENTICAL
 // JAVAC_EXPECTED_FILE
 // FILE: A.java
 abstract public class A extends B {
@@ -11,7 +10,7 @@ import java.util.*;
 
 abstract class B : MutableList<Int>, AbstractList<Int>() {
     override fun removeAt(index: Int): Int = null!!
-    override fun remove(element: Int): <!RETURN_TYPE_MISMATCH_ON_OVERRIDE!>Boolean<!> = null!!
+    override fun remove(element: Int): Boolean = null!!
 }
 
 abstract class D : AbstractList<Int>() {
@@ -20,7 +19,7 @@ abstract class D : AbstractList<Int>() {
     override fun removeAt(index: Int): Int = null!!
     // AbstractList::remove() should return Int here. No fake overrides created.
     // This may be a bug because the old compiler doesn't report a diagnostic here.
-    override fun remove(element: Int): <!RETURN_TYPE_MISMATCH_ON_OVERRIDE!>Boolean<!> = null!!
+    override fun remove(element: Int): Boolean = null!!
 }
 
 fun main(a: A, b: B, c: ArrayList<Int>) {