RFR: 8154500 fix handling of jdk.launcher.patch.* in tests

[Kumar Srinivasan]

Looks fine to me.

Kumar

> The conversion from using sun.boot.class.path to jdk.launcher.patch.* 
> was imperfect, and becoming more so with the move towards using 
> multiple -Xpatch options, in different system properties.
>
> A more complete/general solution would be shared infrastructure to 
> fork tools and inherit selected jdk.launcher properties, but for now, 
> I've done "quick and easy".
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8154500
> Review: http://cr.openjdk.java.net/~jjg/8154500/webrev.00/index.html
>
> -- Jon
>