8173339: AArch64: Fix minimum stack size computations

[Andrew Dinn]

The following webrev against jdk9-dev fixes the AArch64 stack size
computation as JDK-8173339 required by in line with changes made for the
bug which caused it JDK-8170655

  http://cr.openjdk.java.net/~adinn/8173339/webrev.0/

This is proposed for inclusion jdk9 because it is a serious crasher bug.

I'll need reviewers and a sponsor.

regards,


Andrew Dinn
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Senior Principal Software Engineer
Red Hat UK Ltd
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