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/builtinStubMethods/extendJavaCollections/hashMap.kt

@@ -0,0 +1,18 @@
+class A : HashMap<String, Double>()
+
+fun box(): String {
+    val a = A()
+    val b = A()
+
+    a.put("", 0.0)
+    a.remove("")
+
+    a.putAll(b)
+    a.clear()
+
+    a.keys
+    a.values
+    a.entries
+
+    return "OK"
+}