Refactor: extract JVM-specific tests into separate files

Make KotlinVersion random comparison test running in JS

libraries/stdlib/js/test/core/testUtils.kt

@@ -22,6 +22,9 @@ public fun assertTypeEquals(expected: Any?, actual: Any?) {
     assertEquals(expected?.let { it::class.js }, actual?.let { it::class.js })
 }
 
+@Suppress("DEPRECATION")
+public fun randomInt(limit: Int): Int = (kotlin.js.Math.random() * limit).toInt()
+
 @Suppress("NOTHING_TO_INLINE")
 internal inline fun String.removeLeadingPlusOnJava6(): String = this
 internal fun doubleTotalOrderEquals(a: Double?, b: Double?) = a == b || (a != a && b != b)