cmd/coordinator: fix trivial test compilation failure

Change-Id: I8c8a7650c9bf5254791cff84062f6b96178791f3
Reviewed-on: https://go-review.googlesource.com/41754
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/cmd/coordinator/coordinator_test.go b/cmd/coordinator/coordinator_test.go
index 902a584..1a4d104 100644
--- a/cmd/coordinator/coordinator_test.go
+++ b/cmd/coordinator/coordinator_test.go
@@ -14,7 +14,7 @@
 	for name := range fixedTestDuration {
 		in = append(in, name)
 	}
-	sets := partitionGoTests(in)
+	sets := partitionGoTests("", in)
 	for i, set := range sets {
 		t.Logf("set %d = \"-run=^(%s)$\"", i, strings.Join(set, "|"))
 	}