[SLC] throw exception on redundant test data file

analysis/symbol-light-classes/tests/org/jetbrains/kotlin/light/classes/symbol/base/AbstractSymbolLightClassesTestBase.kt

@@ -35,6 +35,7 @@ import java.io.File
 import java.nio.file.Path
 import kotlin.io.path.exists
 import kotlin.io.path.nameWithoutExtension
+import kotlin.test.fail
 
 // Same as LightProjectDescriptor.TEST_MODULE_NAME
 private const val TEST_MODULE_NAME = "light_idea_test_case"
@@ -147,6 +148,7 @@ abstract class AbstractSymbolLightClassesTestBase(
         val identicalCheckerHelper = IdenticalCheckerHelper(testServices)
         if (identicalCheckerHelper.contentsAreEquals(java.toFile(), firJava.toFile(), trimLines = true)) {
             identicalCheckerHelper.deleteFirFile(java.toFile())
+            fail("$firJava is equals to $java. The redundant test data file removed")
         }
     }