Support !LANGUAGE directive in signature tests

compiler/tests-common/tests/org/jetbrains/kotlin/jvm/compiler/AbstractWriteSignatureTest.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. 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.jvm.compiler
@@ -20,6 +9,7 @@ import com.google.common.io.Closeables
 import com.google.common.io.Files
 import com.intellij.openapi.util.Disposer
 import com.intellij.openapi.util.io.FileUtil
+import org.jetbrains.kotlin.checkers.setupLanguageVersionSettingsForCompilerTests
 import org.jetbrains.kotlin.cli.jvm.compiler.KotlinCoreEnvironment
 import org.jetbrains.kotlin.codegen.GenerationUtils
 import org.jetbrains.kotlin.test.ConfigurationKind
@@ -57,6 +47,8 @@ abstract class AbstractWriteSignatureTest : TestCaseWithTmpdir() {
         val ktFile = File(ktFileName)
         val text = FileUtil.loadFile(ktFile, true)
 
+        setupLanguageVersionSettingsForCompilerTests(text, environment!!)
+
         val psiFile = KotlinTestUtils.createFile(ktFile.name, text, environment!!.project)
 
         val fileFactory = GenerationUtils.compileFileTo(psiFile, environment!!, tmpdir)