RFR: 8160213: tools/pack200/Utils.java should clean up javac*.tmp files

[Kumar Srinivasan]

Hello,

Please review fix for: https://bugs.openjdk.java.net/browse/JDK-8160213
Webrev: http://cr.openjdk.java.net/~ksrini/8160213/webrev.00/

Now the temporary javac argument file will be written to the working 
directory
of the test which will be purged upon completion.

The test for MultiRelease did not clean up after itself, added the cleanup
call, please note in the event of a failure, the files will be left 
behind for analysis.

Thanks

Kumar