env/linux-arm/aws, dashboard: add linux-arm-aws builder

This change adds the linux-arm-aws builder. This builder will be
started on a EC2 instance which will spawn a single instance
of the container. After the builder work is done, the instance will be
destroyed.

Updates golang/go#41867

Change-Id: I09d911c2f99d1dff8fe02feb458457e07e7d0cdd
Reviewed-on: https://go-review.googlesource.com/c/build/+/260797
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>
Reviewed-by: Alexander Rakoczy <alex@golang.org>
diff --git a/dashboard/builders.go b/dashboard/builders.go
index 4ce2cbf..4f9b014 100644
--- a/dashboard/builders.go
+++ b/dashboard/builders.go
@@ -525,7 +525,17 @@
 		machineType:     "m6g.xlarge",
 		isEC2:           true,
 		env:             []string{"GOROOT_BOOTSTRAP=/usr/local/go-bootstrap"},
-		buildletURLTmpl: "http://storage.googleapis.com/$BUCKET/buildlet.linux-amd64",
+		buildletURLTmpl: "http://storage.googleapis.com/$BUCKET/buildlet.linux-arm64",
+		SSHUsername:     "root",
+	},
+	"host-linux-arm-aws": &HostConfig{
+		Notes:           "Debian Buster, EC2 arm instance. See x/build/env/linux-arm/aws",
+		VMImage:         "ami-07409163bccd5ac4d",
+		ContainerImage:  "gobuilder-arm-aws:latest",
+		machineType:     "m6g.xlarge",
+		isEC2:           true,
+		env:             []string{"GOROOT_BOOTSTRAP=/usr/local/go-bootstrap"},
+		buildletURLTmpl: "http://storage.googleapis.com/$BUCKET/buildlet.linux-arm",
 		SSHUsername:     "root",
 	},
 	"host-illumos-amd64-jclulow": &HostConfig{
@@ -2290,6 +2300,11 @@
 		HostType: "host-linux-arm64-aws",
 	})
 	addBuilder(BuildConfig{
+		Name:       "linux-arm-aws",
+		HostType:   "host-linux-arm-aws",
+		KnownIssue: 41867, // builder being tested for reliability
+	})
+	addBuilder(BuildConfig{
 		FlakyNet:       true,
 		HostType:       "host-linux-mipsle-mengzhuo",
 		Name:           "linux-mips64le-mengzhuo",