Move HandleUtils to internals package

Author: lolgab

core/src/main/scala/scala/scalanative/loop/Timer.scala

@@ -5,6 +5,7 @@ import scala.concurrent.{Future, Promise}
 import scala.concurrent.duration._
 import LibUV._, LibUVConstants._
 import scala.scalanative.unsafe.Ptr
+import internals.HandleUtils
 
 @inline class Timer private (private val ptr: Ptr[Byte]) extends AnyVal {
   def clear(): Unit = {

core/src/main/scala/scala/scalanative/loop/HandleUtils.scala renamed to core/src/main/scala/scala/scalanative/loop/internals/HandleUtils.scala

@@ -1,4 +1,5 @@
 package scala.scalanative.loop
+package internals
 
 import scala.scalanative.runtime.Intrinsics._
 import scala.scalanative.unsafe.Ptr