Allow fetching /properties from map with comparator (#541)

* Return 0 if both arguments equal to be able to lookup /properties from map

* Fix typo

Author: 0x4a616e

src/main/java/com/networknt/schema/JsonSchema.java

@@ -219,10 +219,13 @@ private Map<String, JsonValidator> read(JsonNode schemaNode) {
     }
 
     /**
-     * A comparator that sorts validators, such such that 'properties' comes before 'required',
+     * A comparator that sorts validators, such that 'properties' comes before 'required',
      * so that we can apply default values before validating required.
      */
     private static Comparator<String> VALIDATOR_SORT = (lhs, rhs) -> {
+        if (lhs.equals(rhs)) {
+            return 0;
+        }
         if (lhs.endsWith("/properties")) {
             return -1;
         }