[aarch64-port-dev ] AARCH64: 8064611: Changes to HotSpot shared code

[Andrew Haley]

http://cr.openjdk.java.net/~aph/aarch64-8064611-5/

I think that I have addressed every point that has been made on this
rather long thread.  The most important change is that the AArch64
port now no longer requires a code cache limit of 128Mb, but I have
still included an arch-specific way to limit the default code cache
size.  The logic behind this is that the extra trampoline stubs (and
the far branches in non-trampoline case) significantly bloat the
generated code and cause us to reach the point where we have to use
the trampolines more quickly.

So, there are now two #defines which can be overridden by targets:
CODE_CACHE_DEFAULT_LIMIT and CODE_CACHE_SIZE_LIMIT.

Thanks,
Andrew.