Fix references from test to main in Gradle JS plugin with default output file

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/Kotlin2JsGradlePluginIT.kt

@@ -72,6 +72,7 @@ class Kotlin2JsGradlePluginIT : BaseGradleIT() {
         project.build("build") {
             assertSuccessful()
             assertFileExists("build/classes/main/kotlin2JsNoOutputFileProject_main.js")
+            assertFileExists("build/classes/test/kotlin2JsNoOutputFileProject_test.js")
         }
     }
 

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin2JsNoOutputFileProject/src/main/kotlin/example/Dummy.kt

@@ -1,4 +1,6 @@
 package example
 
-class Dummy {}
+class Dummy {
+    fun f() {}
+}
 

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin2JsNoOutputFileProject/src/test/kotlin/example/DummyTest.kt

@@ -0,0 +1,8 @@
+package example
+
+class DummyTest {
+    fun test() {
+        Dummy().f()
+    }
+}
+

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/Tasks.kt

@@ -320,8 +320,8 @@ open class Kotlin2JsCompile() : AbstractKotlinCompile<K2JSCompilerArguments>(),
             get() = File(destinationDir, "$moduleName.js")
 
     @Suppress("unused")
-    val outputFile: String?
+    val outputFile: String
-        get() = kotlinOptions.outputFile
+        get() = kotlinOptions.outputFile ?: defaultOutputFile.canonicalPath
 
     init {
         @Suppress("LeakingThis")
@@ -330,6 +330,8 @@ open class Kotlin2JsCompile() : AbstractKotlinCompile<K2JSCompilerArguments>(),
 
     override fun populateCompilerArguments(): K2JSCompilerArguments {
         val args = K2JSCompilerArguments().apply { fillDefaultValues() }
+        args.outputFile = outputFile
+
         val friendDependency = friendTaskName
                 ?.let { project.getTasksByName(it, false).singleOrNull() as? Kotlin2JsCompile }
                 ?.outputFile
@@ -359,10 +361,6 @@ open class Kotlin2JsCompile() : AbstractKotlinCompile<K2JSCompilerArguments>(),
         destinationDir.mkdirs()
         args.freeArgs = args.freeArgs + sourceRoots.kotlinSourceFiles.map { it.absolutePath }
 
-        if (args.outputFile == null) {
-            args.outputFile = defaultOutputFile.canonicalPath
-        }
-
         logger.kotlinDebug("compiling with args ${ArgumentUtils.convertArgumentsToStringList(args)}")
 
         val gradleVersion = getGradleVersion()