RFR: 8007333: [launcher] removes multiple back slashes / trivial fix

[Kumar Srinivasan]

Hello,

Please review trivial fix where the launcher did not parse multiple 
back-slashes
correctly. I also added some additional test contributed by Jim Holmlund.
http://cr.openjdk.java.net/~ksrini/8007333/webrev.0/

Thanks
Kumar