loader/lua: Remove pager shim

Just after 12.2 and before the stable/13 branch, kevans added lpager.c
to provide a pager interface for commands written in lua.  It was merged
into 12.3. Now that 12.2 is long since EOL, we can remove the pager shim
here. Nobody needs that old loader + new lua scripts.  Plus only one
command is affected.

Sponsored by:		Netflix
Reviewed by:		kevans
Differential Revision:	https://reviews.freebsd.org/D44142

stand/lua/cli.lua

@@ -30,18 +30,6 @@ local core = require("core")
 
 local cli = {}
 
-if not pager then
-	-- shim for the pager module that just doesn't do it.
-	-- XXX Remove after 12.2 goes EoL.
-	pager = {
-		open = function() end,
-		close = function() end,
-		output = function(str)
-			printc(str)
-		end,
-	}
-end
-
 -- Internal function
 -- Parses arguments to boot and returns two values: kernel_name, argstr
 -- Defaults to nil and "" respectively.