runtime: merge timerModifiedEarlier and timerModifierLater
Nothing actually needs to know the difference between these
two states, so 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: Ia30699ac92e66467773942e7df1fb21470a6e51a
Reviewed-on: https://go-review.googlesource.com/c/go/+/564119
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Ian Lance Taylor <iant@google.com>