do not flush if Write() failed (#13597)

- Go might reset the internal http.ResponseWriter() to `nil`
  after Write() failure if the go-routine has returned, do not
  flush() such scenarios and avoid spurious flushes() as
  returning handlers always flush.
- fix some racy tests with the console 
- avoid ticker leaks in certain situations

cmd/api-router.go

@@ -24,6 +24,7 @@ import (
 
 	"github.com/gorilla/mux"
 	"github.com/klauspost/compress/gzhttp"
+	"github.com/minio/console/restapi"
 	xhttp "github.com/minio/minio/internal/http"
 	"github.com/minio/minio/internal/logger"
 	"github.com/minio/pkg/wildcard"
@@ -42,6 +43,18 @@ func setHTTPServer(h *xhttp.Server) {
 	globalObjLayerMutex.Unlock()
 }
 
+func newConsoleServerFn() *restapi.Server {
+	globalObjLayerMutex.RLock()
+	defer globalObjLayerMutex.RUnlock()
+	return globalConsoleSrv
+}
+
+func setConsoleSrv(srv *restapi.Server) {
+	globalObjLayerMutex.Lock()
+	globalConsoleSrv = srv
+	globalObjLayerMutex.Unlock()
+}
+
 func newObjectLayerFn() ObjectLayer {
 	globalObjLayerMutex.RLock()
 	defer globalObjLayerMutex.RUnlock()