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/kotlin.test/annotations-common/build.gradle

@@ -14,6 +14,10 @@ pill {
     importAsLibrary = true
 }
 
+tasks.withType(org.jetbrains.kotlin.gradle.dsl.KotlinCompile) {
+    kotlinOptions.freeCompilerArgs += "-Xallow-kotlin-package"
+}
+
 jar {
     manifestAttributes(manifest, project, 'Test')
 }