RFR: JDK-8180198: make bootcycle-images fail with uses of -d64 flags

[Kumar Srinivasan]

Looks good, and thanks for fixing this quickly!.

Kumar

> With the removal of the -d64 flag, bootcycle builds started failing. 
> This patch stops trying to use -d64 completely for the boot jdk since 
> it shouldn't be needed for either JDK 8 or 9. The checks that used 
> this parameter to see if the JVM was 64 bit has been rewritten to 
> instead look at the version string.
>
> This is for JDK 10.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8180198
>
> Webrev: http://cr.openjdk.java.net/~erikj/8180198/webrev.01/
>
> /Erik
>