FIR checker: warn redundant open in interface members properly

compiler/testData/diagnostics/tests/delegation/Delegation_MultipleDelegates.fir.kt

@@ -1,10 +1,10 @@
 // !DIAGNOSTICS: -CONFLICTING_JVM_DECLARATIONS
 interface One {
-  public open fun foo() : Int
+  public <!REDUNDANT_OPEN_IN_INTERFACE!>open<!> fun foo() : Int
   private fun boo() = 10
 }
 interface Two {
-  public open fun foo() : Int
+  public <!REDUNDANT_OPEN_IN_INTERFACE!>open<!> fun foo() : Int
 }
 
 interface OneImpl : One {

compiler/testData/diagnostics/tests/modifiers/openInInterface.fir.kt

@@ -1,10 +0,0 @@
-interface My {
-    open fun foo()
-    open fun bar() {}
-    <!REDUNDANT_MODIFIER!>open<!> abstract fun baz(): Int
-
-    open val x: Int
-    open val y: String
-        get() = ""
-    <!REDUNDANT_MODIFIER!>open<!> abstract val z: Double
-}

compiler/testData/diagnostics/tests/modifiers/openInInterface.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 interface My {
     <!REDUNDANT_OPEN_IN_INTERFACE!>open<!> fun foo()
     open fun bar() {}

compiler/testData/diagnostics/tests/override/kt880.fir.kt

@@ -1,16 +0,0 @@
-// KT-880 Overload resolution ambiguity
-
-public interface I {
-    open fun test() : Unit
-}
-
-abstract public class A() {
-    open public fun test() : Unit {
-    }
-}
-
-public open class T() : A(), I {
-    open fun main() : Unit {
-        test() // Test no "Overload resolution ambiguity" is here
-    }
-}

compiler/testData/diagnostics/tests/override/kt880.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // KT-880 Overload resolution ambiguity
 
 public interface I {