Followup r83885: add JSMin+ 1.3 to use its parser to verify output of JavaScriptMinif...

Followup r83885: add JSMin+ 1.3 to use its parser to verify output of JavaScriptMinifierTest unit test cases. Had to change some of the test cases because they were not valid JavaScript programs -- one of the quoting tests was incorrectly quoted in the PHP sources, and several tests around return, continue, and break keywords failed due to not using them in the contexts that they require.

http://crisp.tweakblogs.net/blog/1856/jsmin+-version-13.html
JSMin+ under MPL 1.1/ GPL 2.0 / LGPL 2.1 license.