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/minusAssign.kt

@@ -0,0 +1,23 @@
+import kotlin.test.*
+import kotlin.comparisons.*
+
+fun box() {
+    // lets use a mutable variable of readonly list
+    val data: List<String> = listOf("cheese", "foo", "beer", "cheese", "wine")
+    var l = data
+    l -= "cheese"
+    assertEquals(listOf("foo", "beer", "cheese", "wine"), l)
+    l = data
+    l -= listOf("cheese", "beer")
+    assertEquals(listOf("foo", "wine"), l)
+    l -= arrayOf("wine", "bar")
+    assertEquals(listOf("foo"), l)
+
+    val ml = arrayListOf("cheese", "cheese", "foo", "beer", "cheese", "wine")
+    ml -= "cheese"
+    assertEquals(listOf("cheese", "foo", "beer", "cheese", "wine"), ml)
+    ml -= listOf("cheese", "beer")
+    assertEquals(listOf("foo", "wine"), ml)
+    ml -= arrayOf("wine", "bar")
+    assertEquals(listOf("foo"), ml)
+}