[K/N] Convert :kotlin-native:Interop:Skia buildscript to kts

Use folder structure from the rest of the project and build it by
the bootstrap compiler.

kotlin-native/Interop/Skia/build.gradle

@@ -1,22 +0,0 @@
-/*
- * Copyright 2010-2023 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
- * that can be found in the LICENSE file.
- */
-
-buildscript {
-    apply from: "$rootDir/kotlin-native/gradle/kotlinGradlePlugin.gradle"
-}
-
-apply plugin: 'kotlin'
-
-dependencies {
-    implementation project(":kotlin-native:Interop:Indexer")
-    implementation project(":kotlin-native:Interop:StubGenerator")
-}
-
-compileKotlin {
-    compilerOptions.optIn = [
-            "kotlinx.cinterop.BetaInteropApi",
-            "kotlinx.cinterop.ExperimentalForeignApi",
-    ]
-}

kotlin-native/Interop/Skia/build.gradle.kts

@@ -0,0 +1,24 @@
+import org.jetbrains.kotlin.gradle.tasks.KotlinJvmCompile
+
+plugins {
+    kotlin("jvm")
+}
+
+dependencies {
+    implementation(project(":kotlin-native:Interop:Indexer"))
+    implementation(project(":kotlin-native:Interop:StubGenerator"))
+}
+
+tasks.withType<KotlinJvmCompile>().configureEach {
+    compilerOptions.optIn.addAll(
+            listOf(
+                    "kotlinx.cinterop.BetaInteropApi",
+                    "kotlinx.cinterop.ExperimentalForeignApi",
+            )
+    )
+}
+
+sourceSets {
+    "main" { projectDefault() }
+    "test" { none() }
+}