Compile unsigned types sourceset with 1.3 and annotate them with SinceKotlin("1.3")

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

@@ -10,6 +10,7 @@ package kotlin
 import kotlin.experimental.*
 
 @Suppress("NON_PUBLIC_PRIMARY_CONSTRUCTOR_OF_INLINE_CLASS")
+@SinceKotlin("1.3")
 public inline class UInt internal constructor(private val data: Int) : Comparable<UInt> {
 
     companion object {
@@ -132,7 +133,11 @@ public inline class UInt internal constructor(private val data: Int) : Comparabl
 
 }
 
+@SinceKotlin("1.3")
 public fun Byte.toUInt(): UInt = UInt(this.toInt() and 0xFF)
+@SinceKotlin("1.3")
 public fun Short.toUInt(): UInt = UInt(this.toInt() and 0xFFFF)
+@SinceKotlin("1.3")
 public fun Int.toUInt(): UInt = UInt(this)
+@SinceKotlin("1.3")
 public fun Long.toUInt(): UInt = UInt(this.toInt())