sync: delete dummy builders_test file

The builders should be happy building errgroup instead now.

Change-Id: I99f549032f771e067b5f7780eba1cc6e91bbdfa5
Reviewed-on: https://go-review.googlesource.com/24962
Run-TryBot: Bryan Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

builders_test.go

diff --git a/builders_test.go b/builders_test.go
deleted file mode 100644
index 39500a3..0000000
--- a/builders_test.go
+++ /dev/null
@@ -1,9 +0,0 @@
-// Copyright 2016 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Temporary file to make the builders happy so there's
-// something buildable in this repo. This can be deleted
-// when other code is added here.
-
-package builders_test