dashboard: skip known missing ios/arm64 builder

We are aware that a builder is missing, and have the tracking issue
golang.org/issue/41610 for resolving that. Add a skip to the tests
so that the build dashboard is green until the work of adding the
builder is complete.

For golang/go#41610.

Change-Id: I69dbeb4c28d5567f24b4570f44715d8b5443365f
Reviewed-on: https://go-review.googlesource.com/c/build/+/257117
Trust: Dmitri Shuralyov <[email protected]>
Run-TryBot: Dmitri Shuralyov <[email protected]>
Reviewed-by: Carlos Amedee <[email protected]>
TryBot-Result: Go Bot <[email protected]>

Author: dmitshur

dashboard/builders.go

@@ -29,6 +29,7 @@ var slowBotAliases = map[string]string{
 	"openbsd-arm64": "",
 	"nacl-arm":      "",
 	"darwin-arm":    "", // TODO(golang.org/issue/37611): Remove once port is removed.
+	"ios-arm64":     "", // TODO(golang.org/issue/41610): Add builder for ios/arm64.
 
 	"386":            "linux-386",
 	"aix":            "aix-ppc64",

dashboard/builders_test.go

@@ -790,6 +790,7 @@ func TestTryBotsCompileAllPorts(t *testing.T) {
 	done["nacl-386"] = true    // removed in Go 1.14
 	done["nacl-arm"] = true    // removed in Go 1.14
 	done["windows-arm"] = true // TODO(golang.org/issue/38607) disabled until builder is replaced
+	done["ios-arm64"] = true   // TODO(golang.org/issue/41610): Add builder for ios/arm64.
 	check := func(goos, goarch string) {
 		if goos == "android" {
 			// TODO(golang.org/issue/25963): support