dashboard: remove darwin-amd64-10_8 builder type

macOS 10.8 is very old and not supported by Go 1.13 nor Go 1.12.
There are no instances of this builder type available because
macOS builders are not created on demand and the ExpectNum value
is set to zero. Remove it and various files related to it.

Fixes golang/go#36560

Change-Id: Ife36624f3695fccff2f5a12af4518e25645b4f0d
Reviewed-on: https://go-review.googlesource.com/c/build/+/215257
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Alexander Rakoczy <alex@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/cmd/buildlet/stage0/Makefile b/cmd/buildlet/stage0/Makefile
index db65729..ad95a63 100644
--- a/cmd/buildlet/stage0/Makefile
+++ b/cmd/buildlet/stage0/Makefile
@@ -69,11 +69,7 @@
 # macstadium uploads all the darwin-amd64 stage0 binary as three
 # different filenames, which is used by four different Mac VM images.
 # See the env/darwin/macstadium/** files for details.
-macstadium: run-builder-darwin-10_8.gz run-builder-darwin-10_10.gz run-builder-darwin-10_11.gz
-
-run-builder-darwin-10_8.gz: FORCE
-	go install golang.org/x/build/cmd/upload
-	upload --verbose --osarch=darwin-amd64 --file=go:golang.org/x/build/cmd/buildlet/stage0 --public --cacheable=false --gzip go-builder-data/$@
+macstadium: run-builder-darwin-10_10.gz run-builder-darwin-10_11.gz
 
 run-builder-darwin-10_10.gz: FORCE
 	go install golang.org/x/build/cmd/upload
diff --git a/dashboard/builders.go b/dashboard/builders.go
index 64cd989..57014de 100644
--- a/dashboard/builders.go
+++ b/dashboard/builders.go
@@ -480,16 +480,6 @@
 		OwnerGithub: "jordanrh1",
 		env:         []string{"GOROOT_BOOTSTRAP=C:\\Data\\Go"},
 	},
-	"host-darwin-10_8": &HostConfig{
-		IsReverse: true,
-		ExpectNum: 0,
-		Notes:     "MacStadium OS X 10.8 VM under VMWare ESXi",
-		env: []string{
-			"GOROOT_BOOTSTRAP=/Users/gopher/go1.4",
-		},
-		SSHUsername:     "gopher",
-		HermeticReverse: false, // TODO: make it so, like 10.12
-	},
 	"host-darwin-10_10": &HostConfig{
 		IsReverse: true,
 		ExpectNum: 3,
@@ -2056,12 +2046,6 @@
 		},
 	})
 	addBuilder(BuildConfig{
-		Name:              "darwin-amd64-10_8",
-		HostType:          "host-darwin-10_8",
-		shouldRunDistTest: macTestPolicy,
-		buildsRepo:        disabledBuilder,
-	})
-	addBuilder(BuildConfig{
 		Name:              "darwin-amd64-10_10",
 		HostType:          "host-darwin-10_10",
 		shouldRunDistTest: macTestPolicy,
diff --git a/env/darwin/macstadium/10_8/.gitignore b/env/darwin/macstadium/10_8/.gitignore
deleted file mode 100644
index fb526f6..0000000
--- a/env/darwin/macstadium/10_8/.gitignore
+++ /dev/null
@@ -1 +0,0 @@
-run.tmp.gz
diff --git a/env/darwin/macstadium/10_8/Makefile b/env/darwin/macstadium/10_8/Makefile
deleted file mode 100644
index f094e23..0000000
--- a/env/darwin/macstadium/10_8/Makefile
+++ /dev/null
@@ -1,9 +0,0 @@
-usage: FORCE
-	# See Makefile targets.
-	exit 1
-
-FORCE:
-
-upload: FORCE
-	go install golang.org/x/build/cmd/upload
-	upload --verbose --gzip --file=run-builder-darwin-10_8.sh -cacheable=false -public=true go-builder-data/run-builder-darwin-10_8.gz
diff --git a/env/darwin/macstadium/10_8/stage0.sh b/env/darwin/macstadium/10_8/stage0.sh
deleted file mode 100755
index 04279ce..0000000
--- a/env/darwin/macstadium/10_8/stage0.sh
+++ /dev/null
@@ -1,24 +0,0 @@
-#!/bin/bash
-
-# This is the file baked into the OS X 10.8 VM image.
-#
-# Normally our VMs & containers actually have the cmd/buildlet/stage0
-# binary baked-in, but the Mac VM images are extra painful to
-# configure, so there's an extra level of indirection in their boot
-# process to give us this point of flexibility. This shell script then
-# downloads run-builder-darwin-10_8.gz which is the cmd/buildlet/stage0
-# binary, compressed.
-
-set -e
-url="https://storage.googleapis.com/go-builder-data/run-builder-darwin-10_8.gz"
-while ! curl -f -o run-builder.gz "$url"; do
-    echo
-    echo "curl failed to fetch $url"
-    echo "Sleeping before retrying..."
-    sleep 2
-done
-
-set -x
-gunzip -f run-builder.gz
-chmod +x run-builder
-exec ./run-builder