[FIR] Bring conflicting overloads errors closer to K1 behavior

#KT-55860 Fixed

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

@@ -1,7 +0,0 @@
-open class Aaa() {
-    fun foo() = 1
-}
-
-open class Bbb() : Aaa() {
-    fun <T> foo() = 2
-}

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

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 open class Aaa() {
     fun foo() = 1
 }

compiler/testData/diagnostics/tests/override/clashesOnInheritance/conflictingInherited.fir.kt

@@ -0,0 +1,31 @@
+// SKIP_TXT
+
+open class A {
+    fun <T> some(s: String): T = null!!
+}
+
+interface I {
+    fun some(text: String) = ""
+}
+
+open <!CONFLICTING_INHERITED_MEMBERS!>class X1<!> : A(), I
+open <!CONFLICTING_INHERITED_MEMBERS!>class X2<!> : X1()
+
+// for some reason no error in K1
+open class B {
+    fun <T> some(s: String): T = null!!
+
+    fun some(text: String) = ""
+}
+
+open class X3 : B()
+open class X4 : X3()
+
+open class C {
+    fun <T> some(s: String): T = null!!
+}
+
+open class X5 : C() {
+    <!CONFLICTING_OVERLOADS!>fun some(text: String)<!> = ""
+}
+open <!CONFLICTING_INHERITED_MEMBERS!>class X6<!> : X5()

compiler/testData/diagnostics/tests/override/clashesOnInheritance/conflictingInherited.kt

@@ -0,0 +1,31 @@
+// SKIP_TXT
+
+open class A {
+    fun <T> some(s: String): T = null!!
+}
+
+interface I {
+    fun some(text: String) = ""
+}
+
+open <!CONFLICTING_INHERITED_MEMBERS!>class X1<!> : A(), I
+open class X2 : X1()
+
+// for some reason no error in K1
+open class B {
+    fun <T> some(s: String): T = null!!
+
+    fun some(text: String) = ""
+}
+
+open class X3 : B()
+open class X4 : X3()
+
+open class C {
+    fun <T> some(s: String): T = null!!
+}
+
+open class X5 : C() {
+    <!CONFLICTING_OVERLOADS!>fun some(text: String)<!> = ""
+}
+open class X6 : X5()

compiler/testData/diagnostics/tests/override/clashesOnInheritance/kt9550.fir.kt

@@ -1,13 +0,0 @@
-interface A {
-    fun <T> foo()
-    fun <T> bar()
-}
-
-interface B {
-    fun foo()
-    fun bar()
-}
-
-<!CONFLICTING_INHERITED_MEMBERS!>interface C1<!> : A, B {
-    override fun bar()
-}

compiler/testData/diagnostics/tests/override/clashesOnInheritance/kt9550.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 interface A {
     fun <T> foo()
     fun <T> bar()