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/collections/CollectionTest/dropLastWhile.kt

@@ -0,0 +1,10 @@
+import kotlin.test.*
+import kotlin.comparisons.*
+
+fun box() {
+    val coll = listOf("Foo", "bare", "abc")
+    assertEquals(coll, coll.dropLastWhile { false })
+    assertEquals(listOf<String>(), coll.dropLastWhile { true })
+    assertEquals(listOf("Foo", "bare"), coll.dropLastWhile { it.length < 4 })
+    assertEquals(listOf("Foo"), coll.dropLastWhile { it.all { it in 'a'..'z' } })
+}