Store Duration value as a multi-range Long

Now precision loss happens at bigger durations.

This changes the binary API due different underlying type of Duration.

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
 
@@ -21,4 +21,16 @@ internal actual fun convertDurationUnit(value: Double, sourceUnit: DurationUnit,
 
     val otherInThis = sourceUnit.convert(1, targetUnit)
     return value / otherInThis
-}
+}
+
+@SinceKotlin("1.5")
+@ExperimentalTime
+internal actual fun convertDurationUnitOverflow(value: Long, sourceUnit: DurationUnit, targetUnit: DurationUnit): Long {
+    return targetUnit.convert(value, sourceUnit)
+}
+
+@SinceKotlin("1.5")
+@ExperimentalTime
+internal actual fun convertDurationUnit(value: Long, sourceUnit: DurationUnit, targetUnit: DurationUnit): Long {
+    return targetUnit.convert(value, sourceUnit)
+}