[Test] Add Fir Identical checkers for signature dump handler

compiler/testData/ir/irText/fakeOverrides/fakeOverrideOfRaw.fir.sig.kt.txt

@@ -1,23 +0,0 @@
-// CHECK:
-//   Mangled name: A
-//   Public signature: /A|null[0]
-class A : Java1 {
-  // CHECK:
-  //   Mangled name: A#<init>(){}
-  //   Public signature: /A.<init>|-5645683436151566731[0]
-  //   Public signature debug description: <init>(){}
-  constructor() /* primary */
-
-  // CHECK JVM_IR:
-  //   Mangled name: A#bar(){}List?
-  //   Public signature: /A.bar|-6805136188302315839[0]
-  //   Public signature debug description: bar(){}List?
-  /* fake */ override fun bar(): List?
-
-  // CHECK:
-  //   Mangled name: A#foo(List?){}
-  //   Public signature: /A.foo|-6260703452578085119[0]
-  //   Public signature debug description: foo(List?){}
-  /* fake */ override fun foo(a: List?): Unit
-
-}

compiler/testData/ir/irText/fakeOverrides/fakeOverrideOfRaw.kt

@@ -1,7 +1,6 @@
 // FIR_IDENTICAL
 // ISSUE: KT-65298
 // TARGET_BACKEND: JVM
-// SEPARATE_SIGNATURE_DUMP_FOR_K2
 // FILE: Java1.java
 
 public class Java1 {
@@ -11,4 +10,4 @@ public class Java1 {
 
 // FILE: 1.kt
 class A : Java1() {
-}
+}