The original unit test is converted to a fuzz test, to be more confident
on future refactors. All sub-tests are converted to seed corpus.
Change-Id: Id0c167ed47729a00ea0614d17746ddcc284697d3
Reviewed-on: https://go-review.googlesource.com/c/go/+/723581
Auto-Submit: Michael Pratt <mpratt@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Dmitri Shuralyov <dmitshur@google.com> Reviewed-by: Michael Pratt <mpratt@google.com>