[Test] Convert IGNORE: NATIVE directives in box tests from A to C

^KT-59057

Merge-request: KT-MR-10747
Merged-by: Vladimir Sukharev <Vladimir.Sukharev@jetbrains.com>

compiler/testData/codegen/box/casts/functions/isFunKSmallJVM.kt

@@ -0,0 +1,18 @@
+// TARGET_BACKEND: JVM
+// TARGET_BACKEND: JVM_IR
+
+// WITH_REFLECT
+
+var Any.extProp: String
+        get() = "extProp"
+        set(x: String) {}
+
+fun box(): String {
+    val epg = Any::extProp.getter
+    val eps = Any::extProp.setter
+
+    if (epg !is Function1<*, *>) return "Failed: epg is Function1<*, *>"
+    if (eps !is Function2<*, *, *>) return "Failed: eps is Function2<*, *, *>"
+
+    return "OK"
+}