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/functions/functionNtoStringGeneric.kt

@@ -0,0 +1,26 @@
+// TODO: muted automatically, investigate should it be ran for JS or not
+// IGNORE_BACKEND: JS
+
+// WITH_REFLECT
+
+import kotlin.test.assertEquals
+
+fun <T> bar(): String {
+    return { t: T -> t }.toString()
+}
+
+class Baz<T, V> {
+    fun <V : T> baz(v: V): String {
+        return (fun(t: List<T>): V = v).toString()
+    }
+}
+
+open class Foo<T, U : List<T>>(val lambda: (T) -> U)
+class Bar<T> : Foo<T, List<T>>({ listOf(it) })
+
+fun box(): String {
+    assertEquals("(T) -> T", bar<String>())
+    assertEquals("(kotlin.collections.List<T>) -> V", Baz<String, Int>().baz<String>(""))
+    assertEquals("(T) -> kotlin.collections.List<T>", Bar<Int>().lambda.toString())
+    return "OK"
+}