dashboard: configure android-amd64-emu as post-submit only

It has been decided in go.dev/issue/53377 for this builder to start
being post-submit only. Update the builder configuration accordingly.

Keep it as a TryBot only in x/mobile, where its signal should still
be a net positive contribution despite the noise in its results.

Fixes golang/go#53377.

Change-Id: I44ee5454bfe2de15e2f41a82900ee2acc37cd211
Reviewed-on: https://go-review.googlesource.com/c/build/+/407615
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Bryan Mills <bcmills@google.com>
diff --git a/dashboard/builders.go b/dashboard/builders.go
index 04f76db..729edd9 100644
--- a/dashboard/builders.go
+++ b/dashboard/builders.go
@@ -2437,7 +2437,7 @@
 	addBuilder(BuildConfig{
 		Name:     "android-386-emu",
 		HostType: "host-android-amd64-emu", // same amd64 host is used for 386 builder
-		Notes:    "Android emulator on GCE",
+		Notes:    "Android emulator on GCE (GOOS=android GOARCH=386)",
 		buildsRepo: func(repo, branch, goBranch string) bool {
 			b := buildRepoByDefault(repo)
 			switch repo {
@@ -2460,11 +2460,12 @@
 	addBuilder(BuildConfig{
 		Name:              "android-amd64-emu",
 		HostType:          "host-android-amd64-emu",
-		Notes:             "Android emulator on GCE",
+		Notes:             "Android emulator on GCE (GOOS=android GOARCH=amd64)",
 		numTryTestHelpers: 3,
 		tryBot: func(repo, branch, goBranch string) bool {
+			// See discussion in go.dev/issue/53377.
 			switch repo {
-			case "go", "mobile", "sys", "net", "tools", "crypto", "sync", "text", "time":
+			case "mobile":
 				return true
 			}
 			return false
diff --git a/dashboard/builders_test.go b/dashboard/builders_test.go
index c404eba..8d11b5b 100644
--- a/dashboard/builders_test.go
+++ b/dashboard/builders_test.go
@@ -92,7 +92,6 @@
 			repo:   "go",
 			branch: "master",
 			want: []string{
-				"android-amd64-emu",
 				"freebsd-amd64-12_3",
 				"js-wasm",
 				"linux-386",
@@ -129,7 +128,6 @@
 			repo:   "go",
 			branch: "release-branch.go1.17",
 			want: []string{
-				"android-amd64-emu",
 				"freebsd-amd64-12_3",
 				"js-wasm",
 				"linux-386",
@@ -169,7 +167,6 @@
 			repo:   "go",
 			branch: "release-branch.go1.16",
 			want: []string{
-				"android-amd64-emu",
 				"freebsd-amd64-12_3",
 				"js-wasm",
 				"linux-386",
@@ -216,7 +213,6 @@
 			repo:   "sys",
 			branch: "master",
 			want: []string{
-				"android-amd64-emu",
 				"freebsd-386-13_0",
 				"freebsd-amd64-12_3",
 				"freebsd-amd64-13_0",
@@ -394,19 +390,20 @@
 		{b("linux-386-softfloat@go1.18", "crypto"), onlyPost},
 		{b("linux-386-softfloat@go1.17", "crypto"), onlyPost},
 
-		{b("android-amd64-emu", "go"), both},
+		{b("android-amd64-emu", "go"), onlyPost},
 		{b("android-amd64-emu", "mobile"), both},
-		{b("android-amd64-emu", "crypto"), both},
-		{b("android-amd64-emu", "net"), both},
-		{b("android-amd64-emu", "sync"), both},
-		{b("android-amd64-emu", "sys"), both},
-		{b("android-amd64-emu", "text"), both},
-		{b("android-amd64-emu", "time"), both},
-		{b("android-amd64-emu", "tools"), both},
+		{b("android-amd64-emu", "crypto"), onlyPost},
+		{b("android-amd64-emu", "net"), onlyPost},
+		{b("android-amd64-emu", "sync"), onlyPost},
+		{b("android-amd64-emu", "sys"), onlyPost},
+		{b("android-amd64-emu", "text"), onlyPost},
+		{b("android-amd64-emu", "time"), onlyPost},
+		{b("android-amd64-emu", "tools"), onlyPost},
 		{b("android-amd64-emu", "website"), none},
 
 		{b("android-386-emu", "go"), onlyPost},
 		{b("android-386-emu", "mobile"), onlyPost},
+		{b("android-386-emu", "crypto"), onlyPost},
 
 		{b("linux-amd64", "net"), both},
 		{b("linux-amd64", "net@1.12"), both},
@@ -498,12 +495,12 @@
 		// a device attached.
 		{b("linux-amd64-androidemu", "mobile"), both},
 
-		// But the emulators run all:
+		// The Android emulator builders can test all repos.
 		{b("android-amd64-emu", "mobile"), both},
 		{b("android-386-emu", "mobile"), onlyPost},
-		{b("android-amd64-emu", "net"), both},
+		{b("android-amd64-emu", "net"), onlyPost},
 		{b("android-386-emu", "net"), onlyPost},
-		{b("android-amd64-emu", "go"), both},
+		{b("android-amd64-emu", "go"), onlyPost},
 		{b("android-386-emu", "go"), onlyPost},
 
 		// Only test tip for js/wasm, and only for some repos: