ComparableTimeMark and specialized TimeSource KT-54082

- Introduce ComparableTimeMark interface extending TimeMark,
and TimeSource.WithComparableMarks - a time source that returns such time marks.
- Implement ComparableTimeMark in ValueTimeMark and AbstractLong/DoubleTimeMark classes.

libraries/stdlib/wasm/src/kotlin/time/TimeSources.kt

@@ -20,7 +20,7 @@ private external fun dateNow(): Double
 
 @SinceKotlin("1.3")
 @ExperimentalTime
-internal actual object MonotonicTimeSource : TimeSource {
+internal actual object MonotonicTimeSource : TimeSource.WithComparableMarks {
     private val performance: ExternalInterfaceType? = tryGetPerformance()
 
     private fun read(): Double =
@@ -31,6 +31,12 @@ internal actual object MonotonicTimeSource : TimeSource {
     actual fun adjustReading(timeMark: ValueTimeMark, duration: Duration): ValueTimeMark =
         ValueTimeMark(sumCheckNaN(timeMark.reading as Double + duration.toDouble(DurationUnit.MILLISECONDS)))
 
+    actual fun differenceBetween(one: ValueTimeMark, another: ValueTimeMark): Duration {
+        val ms1 = one.reading as Double
+        val ms2 = another.reading as Double
+        return if (ms1 == ms2) Duration.ZERO else (ms1 - ms2).milliseconds
+    }
+
     override fun toString(): String =
         if (performance != null) "TimeSource(globalThis.performance.now())" else "TimeSource(Date.now())"
 }