RFR: JDK-8171500: Explicitly set --with-target-bits=64 in 64bit jib profiles

[Tim Bell]

Erik:

> If a user asks Jib to build a profile that is supposed to be 64bit, we
> want configure to fail early if it cannot be done. Currently, if
> configure thinks the build platform only supports 32bit builds, it will
> just default to 32bit. By explicitly setting --with-target-bits=64, we
> instead get a failure. This patch adds the argument to all relevant Jib
> profile configurations.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8171500
>
> Webrev: http://cr.openjdk.java.net/~erikj/8171500/webrev.01/

Looks good.

/Tim