cmd/coordinator: update the count for amd64 Mac Hosts

This change updates the number of Mac hosts that are expected to
connect to the coordinator. There is now a distinction between there
being a amd64 and arm64 Mac hosts. We have reduced the count of amd64
hosts to 8 and have been adding arm64 Macs.

Updates golang/go#45088

Change-Id: I97de966c8398ceb0e5cb31d6bbe688de69efc4a5
Reviewed-on: https://go-review.googlesource.com/c/build/+/307731
Trust: Carlos Amedee <[email protected]>
Run-TryBot: Carlos Amedee <[email protected]>
TryBot-Result: Go Bot <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>

Author: cagedmantis

cmd/coordinator/status.go

@@ -360,7 +360,7 @@ var errFound = errors.New("error= line was found")
 
 func newMacHealthChecker() *healthChecker {
 	var hosts []string
-	const numMacHosts = 10 // physical Mac minis, not reverse buildlet connections
+	const numMacHosts = 8 // physical Mac Pros, not reverse buildlet connections. M1 Macs will be included in seperate checks.
 	for i := 1; i <= numMacHosts; i++ {
 		for _, suf := range []string{"a", "b"} {
 			name := fmt.Sprintf("macstadium_host%02d%s", i, suf)