Improve multi-file test framework in CodegenTestCase

Instead of inheriting from KotlinMultiFileTestWithJava, invoke
KotlinTestUtils.createTestFiles directly. This helps to avoid constructing
unnecessary environment (createEnvironment() was called in setUp, but codegen
tests ignored the created environment because it's not possible to do
generically in codegen tests; the environment kind depends on the source file
usually)

compiler/tests/org/jetbrains/kotlin/codegen/AbstractBlackBoxInlineCodegenTest.kt

@@ -16,14 +16,11 @@
 
 package org.jetbrains.kotlin.codegen
 
-import org.jetbrains.kotlin.checkers.KotlinMultiFileTestWithJava
 import org.jetbrains.kotlin.test.ConfigurationKind
 import java.io.File
 
 abstract class AbstractBlackBoxInlineCodegenTest : AbstractBlackBoxCodegenTest() {
-    override fun doMultiFileTest(
-            file: File, modules: Map<String, KotlinMultiFileTestWithJava<Void, TestFile>.ModuleAndDependencies>, files: List<TestFile>
-    ) {
+    override fun doMultiFileTest(file: File, files: List<TestFile>, javaFilesDir: File?) {
         createEnvironmentWithMockJdkAndIdeaAnnotations(ConfigurationKind.ALL)
         loadMultiFiles(files)
         blackBox()