KT-58046 Promote time sources, time marks, measureTime to stable

libraries/stdlib/jvm/src/kotlin/time/MonoTimeSource.kt

@@ -8,7 +8,6 @@ package kotlin.time
 import kotlin.time.TimeSource.Monotonic.ValueTimeMark
 
 @SinceKotlin("1.3")
-@ExperimentalTime
 internal actual object MonotonicTimeSource : TimeSource.WithComparableMarks {
     private val zero: Long = System.nanoTime()
     private fun read(): Long = System.nanoTime() - zero

libraries/stdlib/jvm/test/time/DurationUnitJVMTest.kt

@@ -9,7 +9,6 @@ import java.util.concurrent.TimeUnit
 import kotlin.test.*
 import kotlin.time.*
 
-@OptIn(ExperimentalTime::class)
 class DurationUnitJVMTest {
     @Test
     fun conversionFromTimeUnit() {

libraries/stdlib/jvm/test/time/TimeMarkJVMTest.kt

@@ -9,7 +9,6 @@ import kotlin.test.*
 import kotlin.time.*
 import kotlin.time.Duration.Companion.nanoseconds
 
-@OptIn(ExperimentalTime::class)
 class TimeMarkJVMTest {
 
     @Test