KPM: Fix JAR naming: put the platform name into appendix, not classifier

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/pm20/KotlinFragmentCompilationOutputsJarArtifact.kt

@@ -9,7 +9,7 @@ import org.gradle.api.artifacts.Dependency
 import org.gradle.jvm.tasks.Jar
 import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.util.disambiguateName
 import org.jetbrains.kotlin.gradle.tasks.locateOrRegisterTask
-import org.jetbrains.kotlin.gradle.utils.dashSeparatedName
+import org.jetbrains.kotlin.gradle.utils.dashSeparatedLowercaseName
 
 /**
  * Registers a [Jar] task with the variant's compilation outputs and attaches this artifact to the given configuration.
@@ -17,7 +17,7 @@ import org.jetbrains.kotlin.gradle.utils.dashSeparatedName
 val KotlinFragmentCompilationOutputsJarArtifact = FragmentArtifacts<KotlinGradleVariant> {
     val jar = project.locateOrRegisterTask<Jar>(fragment.outputsJarTaskName) {
         it.from(fragment.compilationOutputs.allOutputs)
-        it.archiveClassifier.set(dashSeparatedName(fragment.name, fragment.containingModule.moduleClassifier))
+        it.archiveAppendix.set(dashSeparatedLowercaseName(fragment.name, fragment.containingModule.moduleClassifier))
     }
     artifact(jar)
     fragment.project.artifacts.add(Dependency.ARCHIVES_CONFIGURATION, jar)

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/utils/stringUtils.kt

@@ -5,6 +5,8 @@
 
 package org.jetbrains.kotlin.gradle.utils
 
+import java.util.*
+
 internal fun lowerCamelCaseName(vararg nameParts: String?): String {
     val nonEmptyParts = nameParts.mapNotNull { it?.takeIf(String::isNotEmpty) }
     return nonEmptyParts.drop(1).joinToString(
@@ -21,6 +23,14 @@ internal fun dashSeparatedName(vararg nameParts: String?): String {
     return nonEmptyParts.joinToString(separator = "-")
 }
 
+internal fun dashSeparatedLowercaseName(nameParts: Iterable<String?>) =
+    dashSeparatedName(*nameParts.toList().toTypedArray())
+
+internal fun dashSeparatedLowercaseName(vararg nameParts: String?): String {
+    val nonEmptyParts = nameParts.mapNotNull { it?.takeIf(String::isNotEmpty)?.toLowerCase(Locale.ENGLISH) }
+    return nonEmptyParts.joinToString(separator = "-")
+}
+
 internal fun String.decamelize(): String {
     return replace(upperCaseRegex) {
         val (first) = it.destructured