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/reflection/mapping/topLevelProperty.kt

@@ -0,0 +1,30 @@
+// TODO: muted automatically, investigate should it be ran for JS or not
+// IGNORE_BACKEND: JS
+
+// WITH_REFLECT
+
+import kotlin.reflect.jvm.*
+import kotlin.test.assertEquals
+
+var topLevel = "123"
+
+fun box(): String {
+    val p = ::topLevel
+
+    assert(p.javaField != null) { "Fail p field" }
+    val field = p.javaField!!
+    val className = field.getDeclaringClass().getName()
+    assertEquals("TopLevelPropertyKt", className)
+
+    val getter = p.javaGetter!!
+    val setter = p.javaSetter!!
+
+    assertEquals(getter, Class.forName("TopLevelPropertyKt").getMethod("getTopLevel"))
+    assertEquals(setter, Class.forName("TopLevelPropertyKt").getMethod("setTopLevel", String::class.java))
+
+    assert(getter.invoke(null) == "123") { "Fail k getter" }
+    setter.invoke(null, "456")
+    assert(getter.invoke(null) == "456") { "Fail k setter" }
+
+    return "OK"
+}