Add more guards to deserializing SkCustomTypeface

A well-defined font shouldn't have glyphs with infinite bounds nor
try to allocate more memory for path data than exists in the stream.

Change-Id: I3fc8ae83958acbb2d1ad28a5fcf63162253c14fd
Bug: oss-fuzz:49770
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/585956
Owners-Override: Kevin Lubick <kjlubick@google.com>
Reviewed-by: Ben Wagner <bungeman@google.com>
2 files changed