log/slog: use the general regex expression of datetime in TestPanics
When I added this test in CL 514135, I missed the timeRE,
we should use it to make this test more precise.
Change-Id: I486f8e8bbbc3a17166107ef361d242ddf4ea2928
Reviewed-on: https://go-review.googlesource.com/c/go/+/525556
Run-TryBot: Andy Pan <panjf2000@gmail.com> Reviewed-by: Cherry Mui <cherryyz@google.com> Reviewed-by: Jonathan Amsterdam <jba@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>