fix(vim.system): close check handle (#24270)

Fix hang after running vim.system() with sanitizers.

runtime/lua/vim/_system.lua

@@ -287,6 +287,7 @@ function M.run(cmd, opts, on_exit)
         end
       end
       check:stop()
+      check:close()
 
       state.done = true
       state.result = {

test/functional/api/vim_spec.lua

@@ -440,7 +440,7 @@ describe('API', function()
       eq({mode='n', blocking=false}, nvim("get_mode"))
     end)
 
-    it('Does not cause heap buffer overflow with large output', function()
+    it('does not cause heap buffer overflow with large output', function()
       eq(eval('string(range(1000000))'),
          nvim('command_output', 'echo range(1000000)'))
     end)
@@ -4411,8 +4411,6 @@ describe('API', function()
       eq('1', meths.cmd({cmd = 'echo', args = {true}}, {output = true}))
     end)
     describe('first argument as count', function()
-      before_each(clear)
-
       it('works', function()
         command('vsplit | enew')
         meths.cmd({cmd = 'bdelete', args = {meths.get_current_buf()}}, {})

test/functional/lua/ui_spec.lua

@@ -5,7 +5,7 @@ local exec_lua = helpers.exec_lua
 local clear = helpers.clear
 local feed = helpers.feed
 local eval = helpers.eval
-local is_os = helpers.is_os
+local is_ci = helpers.is_ci
 local poke_eventloop = helpers.poke_eventloop
 
 describe('vim.ui', function()
@@ -134,7 +134,7 @@ describe('vim.ui', function()
 
   describe('open()', function()
     it('validation', function()
-      if not is_os('bsd') then
+      if is_ci('github') then
         matches('vim.ui.open: command failed %(%d%): { "[^"]+", "non%-existent%-file" }',
           exec_lua[[local _, err = vim.ui.open('non-existent-file') ; return err]])
       end