[canvaskit] Allow users to load their own fonts

Instead of using the test font(s), now ship with a small
(100k) Monospace font. This can be disabled by:
    compile.sh no_font ...

This saves about 350k (164k gzipped) in binary size.

Bug: skia:
Change-Id: I195e3b35bea86d0f096066c1c6a44a4b602571f3
Reviewed-on: https://skia-review.googlesource.com/c/176580
Reviewed-by: Ben Wagner <bungeman@google.com>
19 files changed