Fix test TextBlob_serialize
Fix test TextBlob_serialize

Previously, this test was passing only because it used the default
typeface. In deserialization code, if the typeface can't be
deserialized, it is replaced with the default typeface. I changed the
test to use a non-default typeface, which caused it to fail. I then
changed the custom typeface serializer/deserializer functions so that
the test passes.

Change-Id: I14e33f7fd18342e76a1fa624ae97fd894e010b6a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/226221
Commit-Queue: Ben Wagner <53965154ffeecc4a10886eab9259e95965f2979a@google.com>
Auto-Submit: Ben Wagner aka dogben <3ef7217be91069877d94f7907ce5479000772cd3@google.com>
Reviewed-by: Ben Wagner <53965154ffeecc4a10886eab9259e95965f2979a@google.com>

google/skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia,HalCanary/skia-hc,HalCanary/skia-hc,aosp-mirror/platform_external_skia,HalCanary/skia-hc,aosp-mirror/platform_external_skia,google/skia,HalCanary/skia-hc,HalCanary/skia-hc,aosp-mirror/platform_external_skia,HalCanary/skia-hc,google/skia,HalCanary/skia-hc,aosp-mirror/platform_external_skia,google/skia,google/skia,HalCanary/skia-hc,google/skia,aosp-mirror/platform_external_skia,google/skia,HalCanary/skia-hc,HalCanary/skia-hc,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia