Drop KPropertyNFromReferenceImpl classes

The only place where their get/set methods were used was in
KPropertyNImpl.Getter.invoke, and it's fine if that results in a reflective
call instead (KPropertyN#getter is not available without kotlin-reflect.jar
anyway). The test data has been changed because a package local Java field is
not accessible via reflection

compiler/testData/codegen/box/reflection/properties/javaStaticField.kt

@@ -2,7 +2,9 @@
 // FILE: J.java
 
 public class J {
-    static String x;
+    public static String x;
+
+    static String packageLocalField;
 }
 
 // FILE: K.kt
@@ -19,5 +21,13 @@ fun box(): String {
     assertEquals("OK", J.x)
     assertEquals("OK", f.getter())
 
+    val pl = J::packageLocalField.getter
+    try {
+        pl()
+        return "Fail: package local field must be inaccessible"
+    } catch (e: Exception) {
+        // OK
+    }
+
     return f.get()
 }