Fix SK_RESTRICT errors in SkColorMatrixFilter

Fix incorrect use of the SK_RESTRICT macro in SkColorMatrixFilter, and re-enable the colormatrix GM test.

MSC was generating incorrect code, assuming that the "result" variable inside the processing functions and the "result" variable in filterSpan*() do not alias, which they do.  I removed the use of SK_RESTRICT from the latter.

I've also removed it from asColorMatrix() and setup().  Although I didn't notice any pointer aliasing in those functions today, performance is not critical and someone might inadvertently introduce aliasing in the future.

[TomH, 2012-01-04 21:46:36]

Oh, proc is writing state->fResult? :(
LGTM

[reed1, 2012-01-04 22:12:53]

LGTM, except that I would like to keep its use in asColorMatrix. In fact, I
think there we should *also* mark the parameter as restrict. That function is
very small and clear.

[TomH, 2012-01-05 18:29:53]

Close me!

[Stephen White, 2012-01-05 18:38:11]

On 2012/01/05 18:29:53, TomH wrote:
> Close me!

Landed as r2963; closing.