MIPS: Use 8-byte alignment on native MIPS targets in Zone allocations.

MIPS: Use 8-byte alignment on native MIPS targets in Zone allocations.

MIPS requires an 8-byte alignment for all allocated memory pointers.

This fixes mjsunit div-mod on MIPS HW with --stress-opt --always-opt.

BUG=
TEST=

[kisg, 2011-10-31 20:25:10]

Please land the following commits together to avoid build errors:
http://codereview.chromium.org/8384021/
http://codereview.chromium.org/8428004/
http://codereview.chromium.org/8387044/
http://codereview.chromium.org/8432010/

Thank you.

[danno, 2011-11-09 12:01:48]

Please remove the platform-specific #if def, let's use 8-byte alignment for all
platforms. After talking with Erik, there is a potential upside by improving
zone allocation alignment, and I'd like to avoid the platform-specific
differences.

[danno, 2011-11-09 12:18:52]

Take that back. Erik is doing some analysis about zone allocation size, let's
wait until we figure out the impact of the extra allocation before making the
change cross platform.

[danno, 2011-11-17 13:29:09]

Erik Corry landed a patch that ensures that allocation that are increments of
8-byte  are 8-byte aligned. If that is sufficient to make this patch
unnecessary, please close this issue. Otherwise let me know.

[kisg, 2011-11-17 22:50:15]

On 2011/11/17 13:29:09, danno wrote:
> Erik Corry landed a patch that ensures that allocation that are increments of
> 8-byte  are 8-byte aligned. If that is sufficient to make this patch
> unnecessary, please close this issue. Otherwise let me know.

Yes, thank you, we were testing it on MIPS and it works fine. closing the issue.