MIPS: Merge IR classes for different bitwise operations AND, OR and XOR into one class.

MIPS: Merge IR classes for different bitwise operations AND, OR and XOR into one class.

Port r9846 (4cd055a).

Original commit message:

Since we already have only one LIR class, it does not make much sense to separate them at the HIR level.

BUG=
TEST=
Committed: http://code.google.com/p/v8/source/detail?r=9859

[kisg, 2011-10-31 20:28:48]

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.

[kisg, 2011-10-31 21:20:47]

On 2011/10/31 20:28:48, kisg wrote:
> 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.

I just realized that I uploaded this commit with the wrong base URL. Do you need
me to reupload?

[fschneider, 2011-11-01 16:07:30]

LGTM.

I'll land it from here.