Fix racy test issues (#24971)

server/channels/api4/remote_cluster.go

@@ -195,7 +195,7 @@ func uploadRemoteData(c *Context, w http.ResponseWriter, r *http.Request) {
 	defer c.LogAuditRec(auditRec)
 	audit.AddEventParameter(auditRec, "upload_id", c.Params.UploadId)
 
-	c.AppContext.SetContext(app.WithMaster(c.AppContext.Context()))
+	c.AppContext = c.AppContext.With(app.RequestContextWithMaster)
 	us, err := c.App.GetUploadSession(c.AppContext, c.Params.UploadId)
 	if err != nil {
 		c.Err = err