[Gradle] Fix defaultSourceSetName usages

^KT-62527 In Progress

libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/plugin/KotlinSourceSetProcessor.kt

@@ -119,7 +119,7 @@ internal abstract class KotlinSourceSetProcessor<T : AbstractKotlinCompile<*>>(
         open class IDEClassesTask : DefaultTask()
         // Workaround: as per KT-26641, when there's a Kotlin compilation with a Java source set, we create another task
         // that has a name composed as '<IDE module name>Classes`, where the IDE module name is the default source set name:
-        val expectedClassesTaskName = "${kotlinCompilation.defaultSourceSetName}Classes"
+        val expectedClassesTaskName = "${kotlinCompilation.defaultSourceSet.name}Classes"
         project.tasks.run {
             val shouldCreateTask = expectedClassesTaskName !in names
             if (shouldCreateTask) {

libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/native/internal/CInteropCommonizerCompositeMetadataJarBundling.kt

@@ -27,7 +27,7 @@ internal suspend fun Project.includeCommonizedCInteropMetadata(metadataKlib: Zip
     val outputDirectory = commonizerTask.commonizedOutputDirectory(commonizerDependencyToken) ?: return
 
     metadataKlib.from(outputDirectory) { spec ->
-        spec.into(cinteropMetadataDirectoryPath(compilation.defaultSourceSetName))
+        spec.into(cinteropMetadataDirectoryPath(compilation.defaultSourceSet.name))
     }
 }