Opt-in to use unsigned types in various internal utils

libraries/stdlib/unsigned/src/kotlin/UProgressionUtil.kt

@@ -3,6 +3,7 @@
  * that can be found in the license/LICENSE.txt file.
  */
 
+@file:UseExperimental(ExperimentalUnsignedTypes::class)
 package kotlin.internal
 
 // (a - b) mod c

libraries/stdlib/unsigned/src/kotlin/UnsignedUtils.kt

@@ -3,6 +3,7 @@
  * that can be found in the license/LICENSE.txt file.
  */
 
+@file:UseExperimental(ExperimentalUnsignedTypes::class)
 package kotlin
 
 internal fun uintCompare(v1: Int, v2: Int): Int = (v1 xor Int.MIN_VALUE).compareTo(v2 xor Int.MIN_VALUE)