Introduce FIR_IDENTICAL for FIR vs old frontend tests #KT-36879 Fixed

compiler/testData/diagnostics/tests/nullabilityAndSmartCasts/PreferExtensionsOnNullableReceiver.fir.kt

@@ -1,9 +0,0 @@
-class Foo {
-    fun foo() {}
-}
-
-fun Any?.foo() {}
-
-fun test(f : Foo?) {
-  f.foo()
-}

compiler/testData/diagnostics/tests/nullabilityAndSmartCasts/PreferExtensionsOnNullableReceiver.kt

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

compiler/testData/diagnostics/tests/nullabilityAndSmartCasts/equalityUnderNotNullCheck.fir.kt

@@ -1,5 +0,0 @@
-fun test(a: Any?) {
-    if (a is String) {
-        a == ""
-    }
-}

compiler/testData/diagnostics/tests/nullabilityAndSmartCasts/equalityUnderNotNullCheck.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 fun test(a: Any?) {
     if (a is String) {
         a == ""

compiler/testData/diagnostics/tests/nullabilityAndSmartCasts/noSenselessNullOnNullableType.fir.kt

@@ -1,21 +0,0 @@
-// FILE: A.java
-
-class A {
-    enum Empty {}
-
-    static Empty foo() { return null; }
-}
-
-// FILE: 1.kt
-
-fun bar() = when (A.foo()) {
-    null -> "null"
-    else -> "else"
-}
-
-fun <T : Number?> baz(t: T) = when (t) {
-    is Int -> "int"
-    is Long -> "long"
-    null -> "null"
-    else -> "else"
-}

compiler/testData/diagnostics/tests/nullabilityAndSmartCasts/noSenselessNullOnNullableType.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // FILE: A.java
 
 class A {

compiler/testData/diagnostics/tests/nullabilityAndSmartCasts/noUnnecessaryNotNullAssertionOnErrorType.fir.kt

@@ -1,7 +0,0 @@
-package a
-
-fun foo() {
-    bar()!!
-}
-
-fun bar() = <!UNRESOLVED_REFERENCE!>aa<!>

compiler/testData/diagnostics/tests/nullabilityAndSmartCasts/noUnnecessaryNotNullAssertionOnErrorType.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 package a
 
 fun foo() {