Revert of Normalize SkXfermode_opts.h argument order as d,s[,aa]. (patchset #1 id...

Revert of Normalize SkXfermode_opts.h argument order as d,s[,aa]. (patchset #1 id:1 of https://codereview.chromium.org/1289903002/ )

Reason for revert:
?

Original issue's description:
> Normalize SkXfermode_opts.h argument order as d,s[,aa].
>
> At head they're s,d[,aa] in SkXfermode_opts.h but Sk4px::Map* expect d,s[,aa]
> so we ended up having to write weird little lambda shims to match impedance.
>
> There's no reason for these to disagree, and d,s[,aa] is the One True Order
> (because no matter what you're doing in graphics, there's always a dst).
>
> Should be no perf or image diff, though I'm suspicious it might help MSVC code generation.
>
> BUG=skia:4117
>
> Committed: https://skia.googlesource.com/skia/+/6028a8476504022fe40b6870b1460b5e4a80969f

TBR=djsollen@google.com,mtklein@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:4117

Review URL: https://codereview.chromium.org/1284363002