[paragraph] Only load typefaces once in tests

Currently the typefaces may be loaded many times resulting in many
copies at once if multiple tests are running at once. Instead, load the
typefaces once.

Change-Id: Ic3ea80886c2a37b7c8493a8ec7dde5af7c9fb5da
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/836436
Commit-Queue: Ben Wagner <bungeman@google.com>
Reviewed-by: Kevin Lubick <kjlubick@google.com>
Reviewed-by: Julia Lavrova <jlavrova@google.com>
1 file changed