Cleanup and merge tests

[stleary]

• Copy the unit tests from JSONObject parsing for self-referencing maps #809 after Add a config flag to disable whitespace trimming #832 is merged - change the stackoverflowException to jsonException, remove code that sets the circular references flag
• Fix some compiler warnings that have been accumulating
  • JSON-java/src/main/java/org/json/JSONArray.java:1366: warning: no description for @return
    @return
  • JSON-java/src/main/java/org/json/XMLParserConfiguration.java:319: warning: no description for @param
    @param closeEmptyTag

[stleary]

Closing due to fixed in #846