[Test] Don't compare descriptors dump if there is no expected .txt file

Descriptors dump has not much sense, because at this point diagnostic
  tests for FE 1.0 mostly used only to compare diagnostics with FIR

compiler/tests-common-new/tests/org/jetbrains/kotlin/test/frontend/classic/handlers/DeclarationsDumpHandler.kt

@@ -32,6 +32,11 @@ import org.jetbrains.kotlin.utils.keysToMap
 import java.util.function.Predicate
 import java.util.regex.Pattern
 
+/**
+ * Compares dump of descriptors if with expected
+ * Dump lays in file testName.txt
+ * If there is no .txt file than handler does nothing
+ */
 class DeclarationsDumpHandler(
     testServices: TestServices
 ) : ClassicFrontendAnalysisHandler(testServices) {
@@ -62,10 +67,10 @@ class DeclarationsDumpHandler(
         }
         val expectedFileName = "${testDataFile.nameWithoutExtension}$prefix.txt"
         val expectedFile = testDataFile.parentFile.resolve(expectedFileName)
+        if (!expectedFile.exists()) return
         assertions.assertEqualsToFile(expectedFile, resultDump)
     }
 
-    @OptIn(ExperimentalStdlibApi::class)
     override fun processModule(module: TestModule, info: ClassicFrontendOutputArtifact) {
         if (DiagnosticsDirectives.SKIP_TXT in module.directives) return
         val moduleDescriptor = info.analysisResult.moduleDescriptor