cmd/compile: test for omitted ICE diagnostics after normal messages
cmd/compile: test for omitted ICE diagnostics after normal messages

Updates #22389

@mdempsky's CL 70850 fixed the unnecessary
compile stack trace printing during ICE diagnostics.

This CL adds a test to lock in this behavior.

Change-Id: I9ce49923c80b78cb8c0bb5dc4af3c860a43d63ba
Reviewed-on: https://go-review.googlesource.com/74630
Run-TryBot: Emmanuel Odeke <277f8eaa8c7dfbc55c17bf5e30561c1a9c45c569@gmail.com>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Matthew Dempsky <e56ac2c500064424afac424d4b5e53bd0570a731@google.com>

josharian/go,CAFxX/go,akutz/go,golang/go,CAFxX/go,cloudflare/go,golang/go,josharian/go,codestation/go,cloudflare/go,codestation/go,Cofyc/go,CAFxX/go,codestation/go,josharian/go,codestation/go,nawawi/go,CAFxX/go,nawawi/go,codestation/go,Cofyc/go,codestation/go,josharian/go,nawawi/go,akutz/go,cloudflare/go,cloudflare/go,golang/go,golang/go,cloudflare/go,CAFxX/go,christopher-henderson/Go,golang/go,akutz/go,Cofyc/go,Cofyc/go,akutz/go,akutz/go,cloudflare/go,golang/go,CAFxX/go,josharian/go,Cofyc/go,nawawi/go,codestation/go,josharian/go,golang/go,nawawi/go,akutz/go,Cofyc/go,cloudflare/go,CAFxX/go,Cofyc/go,akutz/go,Cofyc/go,nawawi/go,josharian/go,nawawi/go,nawawi/go,codestation/go,CAFxX/go,akutz/go,cloudflare/go,golang/go,josharian/go