misc/cgo/testcarchive: increase timeout duration in TestOsSignal
misc/cgo/testcarchive: increase timeout duration in TestOsSignal

This test is slightly flaky on the s390x builder and I suspect that
the 100ms timeout is a little too optimistic when the VM is starved.
Increase the timeout to 5s to match the other part of the test.

Fixes #26231.

Change-Id: Ia6572035fb3efb98749f2c37527d250a4c779477
Reviewed-on: https://go-review.googlesource.com/122315
Run-TryBot: Michael Munday <19411bdeea90f848b8e02e9a1c63a7ce7cc699ea@ibm.com>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>

josharian/go,golang/go,nawawi/go,akutz/go,CAFxX/go,cloudflare/go,akutz/go,josharian/go,nawawi/go,golang/go,cloudflare/go,akutz/go,josharian/go,cloudflare/go,josharian/go,cloudflare/go,golang/go,akutz/go,cloudflare/go,nawawi/go,nawawi/go,nawawi/go,nawawi/go,CAFxX/go,golang/go,CAFxX/go,CAFxX/go,CAFxX/go,josharian/go,akutz/go,nawawi/go,josharian/go,akutz/go,cloudflare/go,CAFxX/go,CAFxX/go,josharian/go,josharian/go,akutz/go,CAFxX/go,golang/go,nawawi/go,golang/go,golang/go,cloudflare/go,golang/go,cloudflare/go,akutz/go