dashboard, cmd/gomote: remove the linux-386-387 builder

The linux-386-387 was only in use for Go 1.15 development. It is being
removed as there is no further development for Go 1.15.

For golang/go#40255
For golang/go#41799

Change-Id: If636c0099bce195e227a5036842ace92e8305fc9
Reviewed-on: https://go-review.googlesource.com/c/build/+/342895
Trust: Carlos Amedee <[email protected]>
Run-TryBot: Carlos Amedee <[email protected]>
TryBot-Result: Go Bot <[email protected]>
Reviewed-by: Alexander Rakoczy <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>

Author: cagedmantis

cmd/gomote/gomote.go

@@ -50,7 +50,7 @@ The "gomote run" command has many of its own flags:
     -builderenv string
           Optional alternate builder to act like. Must share the same
           underlying buildlet host type, or it's an error. For
-          instance, linux-amd64-race or linux-386-387 are compatible
+          instance, linux-amd64-race is compatible
           with linux-amd64, but openbsd-amd64 and openbsd-386 are
           different hosts.
     -debug

dashboard/builders.go

@@ -1548,17 +1548,6 @@ func init() {
 		HostType: "host-linux-stretch",
 		env:      []string{"GOARCH=386", "GOHOSTARCH=386", "GO386=softfloat"},
 	})
-	addBuilder(BuildConfig{
-		Name:  "linux-386-387",
-		Notes: "GO386=387",
-		buildsRepo: func(repo, branch, goBranch string) bool {
-			// GO386=387 is removed in Go 1.16 (golang.org/issue/40255).
-			// It's still supported in Go 1.15.
-			return atMostGo1(goBranch, 15) && (repo == "go" || repo == "crypto")
-		},
-		HostType: "host-linux-jessie",
-		env:      []string{"GOARCH=386", "GOHOSTARCH=386", "GO386=387"},
-	})
 	addBuilder(BuildConfig{
 		Name:       "linux-amd64",
 		HostType:   "host-linux-stretch",

dashboard/builders_test.go

@@ -372,12 +372,6 @@ func TestBuilderConfig(t *testing.T) {
 		{b("linux-386-softfloat", "crypto"), onlyPost},
 		{b("[email protected]", "crypto"), onlyPost},
 		{b("[email protected]", "crypto"), none},
-		{b("linux-386-387", "crypto"), none},
-		{b("[email protected]", "crypto"), none},
-		{b("[email protected]", "crypto"), onlyPost},
-		{b("[email protected]", "[email protected]"), onlyPost},
-		{b("[email protected]", "build"), none},
-		{b("[email protected]", "crypto"), onlyPost},
 		{b("[email protected]", "net"), none},
 		{b("linux-arm-arm5spacemonkey", "exp"), none},
 		{b("linux-arm-arm5spacemonkey", "mobile"), none},