For historical reasons, we have to treat a zero timer as
the same as an initialized timer that was stopped (removed).
The two states are already treated mostly identically.
Merge them.
This is part of a larger simplification of the state set.
[This is one CL in a refactoring stack making very small changes
in each step, so that any subtle bugs that we miss can be more
easily pinpointed to a small change.]
Change-Id: I9c3aeb8f92bafb18c47489c1ec20a7b87ac5cd9c
Reviewed-on: https://go-review.googlesource.com/c/go/+/564122
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Ian Lance Taylor <iant@google.com>