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/callableReference/bound/simpleFunction.kt

@@ -0,0 +1,6 @@
+// Enable when callable references to builtin members is supported
+// IGNORE_BACKEND: JS
+fun box(): String {
+    val f = "KOTLIN"::get
+    return "${f(1)}${f(0)}"
+}