dashboard: add linux-amd64-nounified builder

This builder is identical to the current linux-amd64-unified builder
config, except it sets GOEXPERIMENT=nounified instead to ensure we
maintain coverage after switching the default mode.

Fixes golang/go#51397.

Change-Id: If0ffbf251337db3addce61618784501c7a20283f
Reviewed-on: https://go-review.googlesource.com/c/build/+/388494
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>

dashboard/builders.go

@@ -1750,6 +1750,26 @@ func init() {
 		numTestHelpers:    1,
 		numTryTestHelpers: 4,
 	})
+	addBuilder(BuildConfig{
+		Name:     "linux-amd64-nounified",
+		HostType: "host-linux-buster",
+		Notes:    "builder with GOEXPERIMENT=nounified, see golang.org/issue/51397",
+		tryBot: func(repo, branch, goBranch string) bool {
+			return (repo == "go" || repo == "tools") && (goBranch == "master" || goBranch == "dev.typeparams")
+		},
+		buildsRepo: func(repo, branch, goBranch string) bool {
+			return (repo == "go" || repo == "tools") && (goBranch == "master" || goBranch == "dev.typeparams")
+		},
+		env: []string{
+			"GO_DISABLE_OUTBOUND_NETWORK=1",
+			"GOEXPERIMENT=nounified",
+		},
+		GoDeps: []string{
+			"804ecc2581caf33ae347d6a1ce67436d1f74e93b", // CL 328215, which added GOEXPERIMENT=unified on dev.typeparams
+		},
+		numTestHelpers:    1,
+		numTryTestHelpers: 4,
+	})
 	addBuilder(BuildConfig{
 		Name:     "linux-amd64-goamd64v3",
 		HostType: "host-linux-bullseye",

dashboard/builders_test.go

@@ -99,6 +99,7 @@ func TestTrybots(t *testing.T) {
 				"linux-amd64",
 				"linux-amd64-race",
 				"linux-amd64-unified",
+				"linux-amd64-nounified",
 				"linux-arm-aws",
 				"linux-arm64-aws",
 				"openbsd-amd64-68",
@@ -133,6 +134,7 @@ func TestTrybots(t *testing.T) {
 				"linux-amd64",
 				"linux-amd64-race",
 				"linux-amd64-unified",
+				"linux-amd64-nounified",
 				"linux-arm-aws",
 				"linux-arm64-aws",
 				"openbsd-amd64-68",
@@ -662,6 +664,13 @@ func TestBuilderConfig(t *testing.T) {
 		{b("linux-amd64-unified@dev.typeparams", "go"), both},
 		{b("linux-amd64-unified@dev.typeparams", "tools"), both},
 		{b("linux-amd64-unified@dev.typeparams", "net"), none},
+
+		{b("linux-amd64-nounified", "go"), both},
+		{b("linux-amd64-nounified", "tools"), both},
+		{b("linux-amd64-nounified", "net"), none},
+		{b("linux-amd64-nounified@dev.typeparams", "go"), both},
+		{b("linux-amd64-nounified@dev.typeparams", "tools"), both},
+		{b("linux-amd64-nounified@dev.typeparams", "net"), none},
 	}
 	for _, tt := range tests {
 		t.Run(tt.br.testName, func(t *testing.T) {