RFR(XS): 8132475 : The commands in the modular images are executable by the owner only (once again)

[Volker Simonis]

Hi,

could you please review this tiny change:

http://cr.openjdk.java.net/~simonis/webrevs/2015/8132475/
https://bugs.openjdk.java.net/browse/JDK-8132475

After "8080511: Refresh of jimage support" the executable commands in
jdk/bin and jre/bin are only executable by the file owner. This means
that only the user who built the images can execute the programs.

The fix is trivial, but I've also added a test now so this won't
happen a third time :)

Thank you and best regards,
Volker