add skynet.stat 'time'

test/testendless.lua

@@ -0,0 +1,11 @@
+local skynet = require "skynet"
+
+skynet.start(function()
+	for i = 1, 1000000000 do	-- very long loop
+		if i%100000000 == 0 then
+			print("Endless = ", skynet.stat "endless")
+			print("Cost time = ", skynet.stat "time")
+		end
+	end
+	skynet.exit()
+end)