feat(*) remove the _G write guard log in CLI and rbusted

The newly introduced _G write guard alert log in OpenResty 1.15.8.1 will
be triggered when setting globals in resty-cli, since the wrapping
context is `ngx.timer`. At runtime, Kong should only set the _G.kong
variable during in the `init_by_lua` context, in which the warning would
not show. By disabling the log, this patch makes rbusted behave more
like runtime Kong, and reduces `stderr` output when running tests.

bin/busted

@@ -45,6 +45,8 @@ if not os.getenv("KONG_BUSTED_RESPAWNED") then
   os.exit(rc)
 end
 
+setmetatable(_G, nil)
+
 pcall(require, "luarocks.loader")
 
 require("kong.globalpatches")({

bin/kong

@@ -1,5 +1,7 @@
 #!/usr/bin/env resty
 
+setmetatable(_G, nil)
+
 pcall(require, "luarocks.loader")
 
 package.path = (os.getenv("KONG_LUA_PATH_OVERRIDE") or "") .. "./?.lua;./?/init.lua;" .. package.path

kong/globalpatches.lua

@@ -14,10 +14,18 @@ return function(options)
   ran_before = true
 
 
-
   options = options or {}
   local meta = require "kong.meta"
 
+
+  if options.cli then
+    -- disable the _G write guard alert log introduced in OpenResty 1.15.8.1
+    -- when in CLI or when running tests in resty-cli
+    --local _G_mt = getmetatable(_G)
+    setmetatable(_G, nil)
+  end
+
+
   _G._KONG = {
     _NAME = meta._NAME,
     _VERSION = meta._VERSION