[aarch64-port-dev ] [aarch64-port-dev] RFR 8191338: aarch64: fails to build after 8189745

[Stuart Monteith]

https://bugs.openjdk.java.net/browse/JDK-8191338
http://cr.openjdk.java.net/~smonteith/8191338/webrev/

This fixes an issue whereby on aarch64 platforms without CRC32
instructions, a relative branch to NULL was being generated, which is
out of reach. This is causing my builds on APM X-Gene 1's to fail.


BR,
    Stuart