[Test] Add debug names to unnamed test disposables

- This helps to track down disposables which are never disposed, and
  reduces confusion when printing disposables in general (the names will
  now be meaningful, instead of endless lists of "newDisposable" and
  "TestDisposable").

^KT-64099

compiler/tests/org/jetbrains/kotlin/cli/jvm/repl/GenericReplTest.kt

@@ -199,7 +199,7 @@ internal class TestRepl(
 ) : Closeable {
     val application = ApplicationManager.getApplication()
 
-    private val disposable: Disposable by lazy { Disposer.newDisposable() }
+    private val disposable: Disposable by lazy { Disposer.newDisposable("${TestRepl::class.simpleName}.disposable") }
 
     val emptyScriptArgs = ScriptArgsWithTypes(arrayOf(emptyArray<String>()), arrayOf(Array<String>::class))
 

compiler/tests/org/jetbrains/kotlin/jvm/compiler/FastJarFSTest.kt

@@ -23,7 +23,7 @@ class FastJarFSTest : TestCase() {
 
     private var fs: FastJarFileSystem? = null
     private var coreAppEnv: JavaCoreApplicationEnvironment? = null
-    private val rootDisposable = Disposer.newDisposable()
+    private val rootDisposable = Disposer.newDisposable("${FastJarFSTest::class.simpleName}.rootDisposable")
 
     override fun setUp() {
         super.setUp()

compiler/tests/org/jetbrains/kotlin/serialization/js/KotlinJavascriptSerializerTest.kt

@@ -72,7 +72,7 @@ class KotlinJavascriptSerializerTest : TestCaseWithTmpdir() {
     }
 
     private fun serialize(configuration: CompilerConfiguration, metaFile: File) {
-        val rootDisposable = Disposer.newDisposable()
+        val rootDisposable = Disposer.newDisposable("Disposable for ${KotlinJavascriptSerializerTest::class.simpleName}.serialize")
         try {
             val environment = KotlinCoreEnvironment.createForTests(rootDisposable, configuration, EnvironmentConfigFiles.JS_CONFIG_FILES)
             val files = environment.getSourceFiles()