Today's gm include many differences caused by platform font implementations.

Today's gm include many differences caused by platform font implementations.
This experiment replaces the label used in the aaxfermodes gm with
aliased text generated from paths common to all platforms.

Since there is no way today to generate all dm output from trybots,
this will be checked in to confirm that this strategy provides simpler
output across devices.

This does not introduce a new public interface; instead, dm uses
a extern backdoor to install the SkTypeface::CreateFromName
handler.

Review URL: https://codereview.chromium.org/1163283002