RFR 8210670 (S): Accept double-dash VM-name options at launch time

[mark.reinhold at oracle.com]

2018/9/12 14:16:00 -0700, mark.reinhold at oracle.com:
> ...
> 
> 8210670: Accept double-dash VM-name options at launch time
> 
>   Per JEP 293 (Guidelines for JDK Command-Line Tool Options) [2], enhance
>   the Java launcher so that `--server` is accepted to select the server VM,
>   in addition to `-server`, and likewise for any other VMs listed in the
>   $JDK/lib/jvm.cfg file.
> 
>   JBS: https://bugs.openjdk.java.net/browse/JDK-8210670
>   Webrev: http://cr.openjdk.java.net/~mr/rev/8210670/
> 
> Passes tier1 tests; tier2-3 in progress.

Addendum: Joe reminded me that this change should have a CSR, so here it
is: https://bugs.openjdk.java.net/browse/JDK-8210682 .  A review of that
too would be appreciated.

I’ve also revised the code for this change, and hence the webrev, to
show the double-dash VM-name options in the `java --help` output.

- Mark