[Gradle] Make check for illegal target names case-insensitive

^KT-59733 Verification Pending

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

@@ -85,8 +85,11 @@ private suspend fun Project.illegalTargetNamesUsed(): Set<String> {
     val targetNames = targets.map { it.name }.toSet()
     return targets.flatMap { it.compilations }.mapNotNull { compilation ->
         val hierarchy = KotlinHierarchyTemplate.default.buildHierarchy(compilation) ?: return@mapNotNull null
-        val nodeNames = hierarchy.childrenClosure.mapNotNull { it.node as? KotlinHierarchy.Node.Group }.map { it.name }.toSet()
-        nodeNames.intersect(targetNames)
+        val nodeNames = hierarchy.childrenClosure
+            .mapNotNull { it.node as? KotlinHierarchy.Node.Group }
+            .map { it.name }
+            .toSortedSet(String.CASE_INSENSITIVE_ORDER)
+        targetNames.intersect(nodeNames)
     }.flatten().toSet()
 }
 

libraries/tools/kotlin-gradle-plugin/src/functionalTest/kotlin/org/jetbrains/kotlin/gradle/unitTests/diagnosticsTests/DefaultHierarchySetupDiagnosticTest.kt

@@ -39,7 +39,7 @@ class DefaultHierarchySetupDiagnosticTest {
     fun `test - warning KotlinTargetHierarchyFallbackIllegalTargetNames`() = buildProjectWithMPP().runLifecycleAwareTest {
         val kotlin = multiplatformExtension
         kotlin.linuxX64("linux") // <- illegal: Will clash with 'linux' group
-        kotlin.linuxArm64("native") // <-- illegal: Will clash with 'native' group
+        kotlin.linuxArm64("Native") // <-- illegal: Will clash with 'native' group
         kotlin.jvm()
 
         project.launchInStage(KotlinPluginLifecycle.Stage.ReadyForExecution) {

libraries/tools/kotlin-gradle-plugin/src/functionalTest/resources/expectedDiagnostics/KotlinDefaultHierarchyFallbackIllegalTargetNames.txt

@@ -1,6 +1,6 @@
 [KotlinDefaultHierarchyFallbackIllegalTargetNames | WARNING] The Default Kotlin Hierarchy was not applied to 'root project 'test'':
 Illegal target names were found:
-[native, linux]
+[Native, linux]
 
 To suppress the 'Default Hierarchy Template' add
     'kotlin.mpp.applyDefaultHierarchyTemplate=false'