cmd/compile: run fmt test only in long mode
cmd/compile: run fmt test only in long mode

Update #26469

Change-Id: Id8b8d1c0db48374d5d3dc663a77187a73f60c9a5
Reviewed-on: https://go-review.googlesource.com/125037
Run-TryBot: Keith Randall <8c99c3a9284e493be632950b84cd789d08ed3e9d@golang.org>
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>
Reviewed-by: David Chase <ae171625adc8645b8b79b7e405a6da5aba5341e0@google.com>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>

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