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

[Erik Joelsson]

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