cmd/go/testdata/script: loosen list_empty_importpath for freebsd

We've been seeing the flakes where we get a 'no errors' output on
freebsd in addition to windows and solaris. Also allow that case to
avoid flakes.

For #73976

Change-Id: I6a6a696445ec908b55520d8d75e7c1f867b9c092
Reviewed-on: https://go-review.googlesource.com/c/go/+/715640
Reviewed-by: Alan Donovan <adonovan@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Matloob <matloob@google.com>
Reviewed-by: Ian Alexander <jitsu@google.com>

Author: matloob

src/cmd/go/testdata/script/list_empty_importpath.txt

@@ -1,12 +1,15 @@
 ! go list all
 ! stderr 'panic'
-[!GOOS:windows] [!GOOS:solaris] stderr 'invalid import path'
-# #73976: Allow 'no errors' on Windows and Solaris until issue
+[!GOOS:windows] [!GOOS:solaris] [!GOOS:freebsd] [!GOOS:openbsd] [!GOOS:netbsd] stderr 'invalid import path'
+# #73976: Allow 'no errors' on Windows, Solaris, and BSD until issue
 # is resolved to prevent flakes. 'no errors' is printed by
 # empty scanner.ErrorList errors so that's probably where the
 # message is coming from, though we don't know how.
 [GOOS:windows] stderr 'invalid import path|no errors'
 [GOOS:solaris] stderr 'invalid import path|no errors'
+[GOOS:freebsd] stderr 'invalid import path|no errors'
+[GOOS:openbsd] stderr 'invalid import path|no errors'
+[GOOS:netbsd] stderr 'invalid import path|no errors'
 
 # go list produces a package for 'p' but not for ''
 go list -e all