Prepare project for Kotlin migration (#1257)

examples/build.gradle.kts

@@ -14,19 +14,11 @@
  * limitations under the License.
  */
 
-import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
-
 plugins {
   kotlin("jvm")
   kotlin("kapt")
 }
 
-tasks.withType<KotlinCompile>().configureEach {
-  kotlinOptions {
-    freeCompilerArgs = listOf("-progressive")
-  }
-}
-
 dependencies {
   kapt(project(":kotlin:codegen"))
   compileOnly(Dependencies.jsr305)