os/signal: increase wait time for signal delivery time in testcase
This increases the time to wait from 1 to 2 seconds in the
TestAtomicStop testcase. When running with gccgo on ppc64
& ppc64le on a loaded systems these testcases can
intermittently fail with the current value.
Updates #29046
Change-Id: If420274dd65926d933a3024903b5c757c300bd60
Reviewed-on: https://go-review.googlesource.com/c/153826
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>