[Test] Migrate FIR diagnostic spec tests to new infrastructure

This commit includes a lot of minor changes in testdata: new infrastructure
  requires that each test file in one testdata file in one module must
  have unique name, but a lot of existing spec tests didn't satisfy
  this requirement

compiler/tests-common-new/tests/org/jetbrains/kotlin/test/directives/AdditionalFilesDirectives.kt

@@ -37,4 +37,11 @@ object AdditionalFilesDirectives : SimpleDirectivesContainer() {
             See file ./compiler/testData/diagnostics/helpers/coroutines/TailCallOptimizationChecker.kt
         """.trimIndent()
     )
+
+    val SPEC_HELPERS by directive(
+        description = """
+            Adds util functions from `test-spec` modules
+            See directory ./compiler/tests-spec/helpers/
+        """.trimIndent()
+    )
 }

compiler/tests-common-new/tests/org/jetbrains/kotlin/test/runners/AbstractFirDiagnosticTestSpec.kt

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.test.runners
+
+import org.jetbrains.kotlin.test.builders.TestConfigurationBuilder
+import org.jetbrains.kotlin.test.directives.AdditionalFilesDirectives.SPEC_HELPERS
+import org.jetbrains.kotlin.test.directives.JvmEnvironmentConfigurationDirectives.WITH_STDLIB
+import org.jetbrains.kotlin.test.frontend.fir.FirFailingTestSuppressor
+import org.jetbrains.kotlin.test.frontend.fir.handlers.FirIdenticalChecker
+import org.jetbrains.kotlin.test.services.fir.FirOldFrontendMetaConfigurator
+import org.jetbrains.kotlin.test.services.sourceProviders.SpecHelpersSourceFilesProvider
+
+abstract class AbstractFirDiagnosticTestSpec : AbstractFirDiagnosticTest() {
+    override fun configure(builder: TestConfigurationBuilder) {
+        super.configure(builder)
+        with(builder) {
+            defaultDirectives {
+                +SPEC_HELPERS
+                +WITH_STDLIB
+            }
+
+            useAdditionalSourceProviders(::SpecHelpersSourceFilesProvider)
+
+            useAfterAnalysisCheckers(
+                ::FirIdenticalChecker,
+                ::FirFailingTestSuppressor,
+            )
+
+            useMetaTestConfigurators(::FirOldFrontendMetaConfigurator)
+        }
+    }
+}

compiler/tests-common-new/tests/org/jetbrains/kotlin/test/services/sourceProviders/SpecHelpersSourceFilesProvider.kt

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.test.services.sourceProviders
+
+import org.jetbrains.kotlin.test.directives.AdditionalFilesDirectives
+import org.jetbrains.kotlin.test.directives.AdditionalFilesDirectives.SPEC_HELPERS
+import org.jetbrains.kotlin.test.directives.model.DirectivesContainer
+import org.jetbrains.kotlin.test.directives.model.RegisteredDirectives
+import org.jetbrains.kotlin.test.model.TestFile
+import org.jetbrains.kotlin.test.model.TestModule
+import org.jetbrains.kotlin.test.services.AdditionalSourceProvider
+import org.jetbrains.kotlin.test.services.TestServices
+import java.io.File
+
+class SpecHelpersSourceFilesProvider(testServices: TestServices) : AdditionalSourceProvider(testServices) {
+    companion object {
+        const val HELPERS_DIR_PATH = "compiler/tests-spec/testData/diagnostics/helpers"
+    }
+
+    override val directives: List<DirectivesContainer> =
+        listOf(AdditionalFilesDirectives)
+
+    override fun produceAdditionalFiles(globalDirectives: RegisteredDirectives, module: TestModule): List<TestFile> {
+        if (SPEC_HELPERS !in module.directives) return emptyList()
+        return File(HELPERS_DIR_PATH).walkTopDown().mapNotNull {
+            if (it.isDirectory) return@mapNotNull null
+            it.toTestFile()
+        }.toList()
+    }
+}