cmd/buildlet, cmd/buildlet/stage0: remove references to removed builder

This removes the remaining references to the removed
linux-arm-arm5spacemonkey builders.

For golang/go#41027

Change-Id: I3df249ab6f7180a67d76a2ae037731f7223b8cbb
Reviewed-on: https://go-review.googlesource.com/c/build/+/346531
Trust: Carlos Amedee <carlos@golang.org>
Run-TryBot: Carlos Amedee <carlos@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>

Author: cagedmantis

cmd/buildlet/buildlet.go

@@ -122,14 +122,9 @@ const (
 
 func main() {
 	builderEnv := os.Getenv("GO_BUILDER_ENV")
-
-	switch builderEnv {
-	case "macstadium_vm":
+	if builderEnv == "macstadium_vm" {
 		configureMacStadium()
-	case "linux-arm-arm5spacemonkey":
-		initBaseUnixEnv() // Issue 28041
 	}
-
 	onGCE := metadata.OnGCE()
 	switch runtime.GOOS {
 	case "plan9":

cmd/buildlet/stage0/stage0.go

@@ -78,7 +78,7 @@ func main() {
 	switch osArch {
 	case "linux/arm":
 		switch env := os.Getenv("GO_BUILDER_ENV"); env {
-		case "linux-arm-arm5spacemonkey", "host-linux-arm-aws":
+		case "host-linux-arm-aws":
 			// No setup currently.
 		default:
 			panic(fmt.Sprintf("unknown/unspecified $GO_BUILDER_ENV value %q", env))
@@ -149,9 +149,6 @@ Download:
 	buildEnv := os.Getenv("GO_BUILDER_ENV")
 
 	switch buildEnv {
-	case "linux-arm-arm5spacemonkey":
-		cmd.Args = append(cmd.Args, reverseHostTypeArgs("host-linux-arm5spacemonkey")...)
-		cmd.Args = append(cmd.Args, os.ExpandEnv("--workdir=${WORKDIR}"))
 	case "host-linux-arm-aws":
 		cmd.Args = append(cmd.Args, os.ExpandEnv("--workdir=${WORKDIR}"))
 	case "host-linux-arm64-aws":
@@ -310,11 +307,6 @@ func buildletURL() string {
 		return v
 	}
 
-	switch os.Getenv("GO_BUILDER_ENV") {
-	case "linux-arm-arm5spacemonkey":
-		return "https://storage.googleapis.com/go-builder-data/buildlet.linux-arm-arm5"
-	}
-
 	if metadata.OnGCE() {
 		v, err := metadata.InstanceAttributeValue(attr)
 		if err == nil {