backend/tests: Add blackbox tests from Kotlin JVM

Added tests from testData/codegen/box directory. There are blackbox tests
in other directories and they are to be added.

backend.native/tests/external/codegen/blackbox/reified/copyToArray.kt

@@ -0,0 +1,17 @@
+// WITH_RUNTIME
+
+import kotlin.test.assertEquals
+
+inline fun <reified T> copy(c: Collection<T>): Array<T> {
+    return c.toTypedArray()
+}
+
+fun box(): String {
+    val a: Array<String> = copy(listOf("a", "b", "c"))
+    assertEquals("abc", a.joinToString(""))
+
+    val b: Array<Int> = copy(listOf(1,2,3))
+    assertEquals("123", b.map { it.toString() }.joinToString(""))
+
+    return "OK"
+}