RFR: AArch64: Fix error introduced into AArch64 CodeCache by commit for 8130309

[Andrew Dinn]

The following /AArch64-only/ webrev fixes some problems introduced into
the AArch64 codecache routines by the recent fix for JDK-8130309
committed to to hs-comp

  http://cr.openjdk.java.net/~adinn/8132875/webrev.00/

With this patch the hs-comp tree compiles and runs correctly on AArch64.
Reviews welcome.

regards,


Andrew Dinn
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