[Tests] FIR support in JUnit 3 tests, port necessary subclasses

^KT-64404 Fixed
^KT-64438 Fixed
^KT-64407 Fixed

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

@@ -25,9 +25,8 @@ import kotlin.script.experimental.annotations.KotlinScript
 import kotlin.script.experimental.jvm.defaultJvmScriptingHostConfiguration
 import kotlin.script.experimental.jvm.util.scriptCompilationClasspathFromContextOrStdlib
 
-class CustomScriptCodegenTest : CodegenTestCase() {
-
-    fun testAnnotatedDefinition() {
+open class CustomScriptCodegenTest : CodegenTestCase() {
+    open fun testAnnotatedDefinition() {
         createScriptTestEnvironment("org.jetbrains.kotlin.codegen.TestScriptWithAnnotatedBaseClass")
         loadScript("val x = 1")
         val res = generateScriptClass()
@@ -42,6 +41,9 @@ class CustomScriptCodegenTest : CodegenTestCase() {
         myFiles = CodegenTestFiles.create("scriptTest.kts", text, myEnvironment.project)
     }
 
+    override val backend: TargetBackend
+        get() = TargetBackend.JVM
+
     private fun createScriptTestEnvironment(vararg scriptDefinitions: String) {
         if (myEnvironment != null) {
             throw IllegalStateException("must not set up myEnvironment twice")
@@ -60,7 +62,6 @@ class CustomScriptCodegenTest : CodegenTestCase() {
         val configuration = createConfiguration(
             ConfigurationKind.ALL,
             TestJdkKind.MOCK_JDK,
-            TargetBackend.JVM,
             additionalDependencies,
             emptyList(),
             emptyList()