Fix accidental overrides computation

Consider the whole overridden tree instead of only direct overridden

 #KT-14146 Fixed

compiler/testData/diagnostics/tests/duplicateJvmSignature/accidentalOverrides/accidentalOverrideFromGrandparent.kt

@@ -0,0 +1,14 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+interface Foo<X> {
+    fun foo(x: X)
+}
+
+open class FooImpl : Foo<String> {
+    override fun foo(x: String) {
+    }
+}
+
+open class FooImpl2 : FooImpl() {
+    <!ACCIDENTAL_OVERRIDE!>fun foo(x: Any)<!> {
+    }
+}

compiler/testData/diagnostics/tests/duplicateJvmSignature/accidentalOverrides/accidentalOverrideFromGrandparent.txt

@@ -0,0 +1,25 @@
+package
+
+public interface Foo</*0*/ X> {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract fun foo(/*0*/ x: X): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public open class FooImpl : Foo<kotlin.String> {
+    public constructor FooImpl()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ fun foo(/*0*/ x: kotlin.String): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public open class FooImpl2 : FooImpl {
+    public constructor FooImpl2()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final fun foo(/*0*/ x: kotlin.Any): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun foo(/*0*/ x: kotlin.String): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}