tests: Copy stdlib tests from Kotlin/JVM

This patch copies Kotlin/JVM stdlib tests (libraries/stdlib/test)
excepting ones with explicit java dependencies. It also transforms
the tests to use them as box-tests.

backend.native/tests/external/stdlib/utils/KotlinVersionTest/currentVersion.kt

@@ -0,0 +1,14 @@
+import kotlin.test.*
+
+
+fun box() {
+    assertTrue(KotlinVersion.CURRENT.isAtLeast(1, 1))
+    assertTrue(KotlinVersion.CURRENT.isAtLeast(1, 1, 0))
+    assertTrue(KotlinVersion.CURRENT >= KotlinVersion(1, 1))
+    assertTrue(KotlinVersion(1, 1) <= KotlinVersion.CURRENT)
+
+    val anotherCurrent = KotlinVersion.CURRENT.run { KotlinVersion(major, minor, patch) }
+    assertEquals(KotlinVersion.CURRENT, anotherCurrent)
+    assertEquals(KotlinVersion.CURRENT.hashCode(), anotherCurrent.hashCode())
+    assertEquals(0, KotlinVersion.CURRENT.compareTo(anotherCurrent))
+}