internal/relui: use LongTestBuilder again

Bring back the 'LongTest' bit before 'Builder' that CL 419415 dropped.

The test case I could find on short notice is functional today but
awful. It should be replaced by something better that would catch if
the fake all.bash didn't run on the expected builders. Plumbing that
through seems to need a bigger change and is left for later.

For golang/go#29252.

Change-Id: Ie55309a2deef931b2531cf25b56e3ad635fc96d3
Reviewed-on: https://go-review.googlesource.com/c/build/+/503757
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>

internal/relui/buildrelease_test.go

@@ -750,6 +750,10 @@ type testLogger struct {
 }
 
 func (l *testLogger) Printf(format string, v ...interface{}) {
+	if l.task == "linux-amd64: Run long tests" && fmt.Sprintf(format, v...) == "Creating buildlet linux-amd64-bullseye." {
+		// TODO: This is very brittle; replace with a better way to test this property hasn't regressed.
+		l.t.Errorf("task %q logged creation of a non-longtest buildlet", l.task)
+	}
 	l.t.Logf("task %-10v: LOG: %s", l.task, fmt.Sprintf(format, v...))
 }
 

internal/relui/workflows.go

@@ -507,7 +507,7 @@ func (tasks *BuildReleaseTasks) addBuildTasks(wd *wf.Definition, major int, vers
 		short := wf.Action3(wd, "Run short tests", tasks.runTests, wf.Const(dashboard.Builders[target.Builder]), skipTests, tar)
 		blockers = append(blockers, short)
 		if target.LongTestBuilder != "" {
-			long := wf.Action3(wd, "Run long tests", tasks.runTests, wf.Const(dashboard.Builders[target.Builder]), skipTests, tar)
+			long := wf.Action3(wd, "Run long tests", tasks.runTests, wf.Const(dashboard.Builders[target.LongTestBuilder]), skipTests, tar)
 			blockers = append(blockers, long)
 		}
 	}