all: remove go1.13 and go1.16 build constraints

This change removes the go1.13 and go1.16 build constraints since they are no
longer needed.

Change-Id: I4428d4bc6df7d02d788dbdf6a5329dbd0d5e095b
Reviewed-on: https://go-review.googlesource.com/c/build/+/371454
Trust: Carlos Amedee <carlos@golang.org>
Run-TryBot: Carlos Amedee <carlos@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
diff --git a/cmd/buildlet/reverse_test.go b/cmd/buildlet/reverse_test.go
index 36b7bdc..44c7b24 100644
--- a/cmd/buildlet/reverse_test.go
+++ b/cmd/buildlet/reverse_test.go
@@ -3,8 +3,7 @@
 // license that can be found in the LICENSE file.
 
 // Same requirements as internal/coordinator/pool/reverse.go.
-//go:build go1.13 && (linux || darwin)
-// +build go1.13
+//go:build linux || darwin
 // +build linux darwin
 
 package main
diff --git a/cmd/coordinator/internal/dashboard/datastore.go b/cmd/coordinator/internal/dashboard/datastore.go
index 2d8192c..ac43d15 100644
--- a/cmd/coordinator/internal/dashboard/datastore.go
+++ b/cmd/coordinator/internal/dashboard/datastore.go
@@ -2,8 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build go1.13 && (linux || darwin)
-// +build go1.13
+//go:build linux || darwin
 // +build linux darwin
 
 package dashboard
diff --git a/cmd/coordinator/internal/dashboard/datastore_test.go b/cmd/coordinator/internal/dashboard/datastore_test.go
index 95fd9cd..802252b 100644
--- a/cmd/coordinator/internal/dashboard/datastore_test.go
+++ b/cmd/coordinator/internal/dashboard/datastore_test.go
@@ -2,8 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build go1.13 && (linux || darwin)
-// +build go1.13
+//go:build linux || darwin
 // +build linux darwin
 
 package dashboard
diff --git a/cmd/coordinator/internal/dashboard/handler.go b/cmd/coordinator/internal/dashboard/handler.go
index f2d7fd0..e8a5931 100644
--- a/cmd/coordinator/internal/dashboard/handler.go
+++ b/cmd/coordinator/internal/dashboard/handler.go
@@ -2,8 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build go1.13 && (linux || darwin)
-// +build go1.13
+//go:build linux || darwin
 // +build linux darwin
 
 // Package dashboard contains the implementation of the build dashboard for the Coordinator.
diff --git a/cmd/coordinator/internal/dashboard/handler_test.go b/cmd/coordinator/internal/dashboard/handler_test.go
index 79389cf..505d607 100644
--- a/cmd/coordinator/internal/dashboard/handler_test.go
+++ b/cmd/coordinator/internal/dashboard/handler_test.go
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build go1.13 && linux
-// +build go1.13,linux
+//go:build linux
+// +build linux
 
 package dashboard
 
diff --git a/cmd/updatestd/updatestd_test.go b/cmd/updatestd/updatestd_test.go
index 324dc8a..4ddda5e 100644
--- a/cmd/updatestd/updatestd_test.go
+++ b/cmd/updatestd/updatestd_test.go
@@ -2,9 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build go1.14
-// +build go1.14
-
 package main
 
 import (
diff --git a/internal/coordinator/schedule/fake_schedule.go b/internal/coordinator/schedule/fake_schedule.go
index 3d58303..bf30884 100644
--- a/internal/coordinator/schedule/fake_schedule.go
+++ b/internal/coordinator/schedule/fake_schedule.go
@@ -2,8 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build go1.13 && (linux || darwin)
-// +build go1.13
+//go:build linux || darwin
 // +build linux darwin
 
 package schedule
diff --git a/internal/coordinator/schedule/schedule.go b/internal/coordinator/schedule/schedule.go
index 8e98d07..40a4297 100644
--- a/internal/coordinator/schedule/schedule.go
+++ b/internal/coordinator/schedule/schedule.go
@@ -2,8 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build go1.16 && (linux || darwin)
-// +build go1.16
+//go:build linux || darwin
 // +build linux darwin
 
 package schedule
diff --git a/internal/coordinator/schedule/schedule_test.go b/internal/coordinator/schedule/schedule_test.go
index f40234d..94eb295 100644
--- a/internal/coordinator/schedule/schedule_test.go
+++ b/internal/coordinator/schedule/schedule_test.go
@@ -2,8 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build go1.16 && (linux || darwin)
-// +build go1.16
+//go:build linux || darwin
 // +build linux darwin
 
 package schedule