RFR 8138579: Custom launcher fails to start because of permission problem

[Jaroslav Bachorik]

Please, review the following test change

Issue : https://bugs.openjdk.java.net/browse/JDK-8138579
Webrev: http://cr.openjdk.java.net/~jbachorik/8138579/webrev.00

This test is exercising a custom launcher (executable). Since it is not 
possible to check in a file and prevent its executable flag the test 
sets the executable flag on the fly after it has copied over the 
platform specific launcher to a well known location.

However, setting the executable flag has started to fail on Solaris 
machines recently. I tracked down the failure to the fact that the 
launcher is being copied with the preserved attributes - including the 
owner and group. The original launcher owner and group differ from the 
user the test is run under and therefore the attempt to set the 
executable flag fails.

The proposed fix is not to preserve the file attributes - the launcher 
will be owned by the current user and the attempt to set the executable 
flag will succeed.

The patch has been tested on all supported platforms successfully.

Thanks,

-JB-