Do not blank opt in for allowing kotlin package in all subprojects

-Xallow-kotlin-package must be specified explicitly to prevent
unintended declarations in kotlin package.

libraries/scripting/jvm-host/build.gradle.kts

@@ -28,5 +28,9 @@ sourceSets {
     "test" {}
 }
 
+tasks.withType<org.jetbrains.kotlin.gradle.dsl.KotlinCompile<*>> {
+    kotlinOptions.freeCompilerArgs += "-Xallow-kotlin-package"
+}
+
 standardPublicJars()