Alter GM's --mpd option to write out images

Review URL: https://codereview.chromium.org/811863002
Change desktop and ES 3.0 to always use sized internal texture formats.

Committed: https://skia.googlesource.com/skia/+/bc02bf0ee4221604796cd6d0394ca3af60c0a579

Review URL: https://codereview.chromium.org/806943002
Massive rebaseline for SkRandom.

All of the following GMs have been switched from SkLCGRandom to
SkRandom. Update their expectations for the new images.

-beziers
-circles
-convexpaths
-complexclip2
-complexclip2_rect_aa
-complexclip2_rect_bw
-complexclip2_path_aa
-complexclip2_path_bw
-complexclip2_rrect_aa
-complexclip2_rrect_bw
-cubicpath
-cubicclosepath
-degeneratesegments
-emptypath
-getpostextpath
-hittestpath
-linepath
-lineclosepath
-points
-polygons
-quadpath
-quadclosepath
-strokerects
-strokes_round
-strokes_poly

BUG=skia:3241
TBR=mtklein

Review URL: https://codereview.chromium.org/806263002