The SkDescriptor fuzzer did not call init. This caused
mysterious failures.
Make SkDescriptor's constructor initialize its fields.
Remove init().
Change-Id: Icab79c53b2d2878fceecfec06c886b71613cea6f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/260287
Reviewed-by: Mike Klein <mtklein@google.com>
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Herb Derby <herb@google.com>
26300d64ca