win: test: disable non-admin failing tests

mkfifo (msysgit) does not work outside of msys2 environment.
gzip tests fail on Windows.

mklink requires admin privs for file symbolic links so mklink fails.

test/functional/ex_cmds/write_spec.lua

@@ -9,6 +9,7 @@ local command = helpers.command
 local feed_command = helpers.feed_command
 local funcs = helpers.funcs
 local meths = helpers.meths
+local iswin = helpers.iswin
 
 local fname = 'Xtest-functional-ex_cmds-write'
 local fname_bak = fname .. '~'
@@ -34,7 +35,7 @@ describe(':write', function()
   it('&backupcopy=auto preserves symlinks', function()
     command('set backupcopy=auto')
     write_file('test_bkc_file.txt', 'content0')
-    if helpers.iswin() then
+    if iswin() then
       command("silent !mklink test_bkc_link.txt test_bkc_file.txt")
     else
       command("silent !ln -s test_bkc_file.txt test_bkc_link.txt")
@@ -51,7 +52,7 @@ describe(':write', function()
   it('&backupcopy=no replaces symlink with new file', function()
     command('set backupcopy=no')
     write_file('test_bkc_file.txt', 'content0')
-    if helpers.iswin() then
+    if iswin() then
       command("silent !mklink test_bkc_link.txt test_bkc_file.txt")
     else
       command("silent !ln -s test_bkc_file.txt test_bkc_link.txt")
@@ -66,7 +67,8 @@ describe(':write', function()
   end)
 
   it("appends FIFO file", function()
-    if eval("executable('mkfifo')") == 0 then
+    -- mkfifo creates read-only .lnk files on Windows
+    if iswin() or eval("executable('mkfifo')") == 0 then
       pending('missing "mkfifo" command', function()end)
       return
     end
@@ -88,7 +90,7 @@ describe(':write', function()
     command('let $HOME=""')
     eq(funcs.fnamemodify('.', ':p:h'), funcs.fnamemodify('.', ':p:h:~'))
     -- Message from check_overwrite
-    if not helpers.iswin() then
+    if not iswin() then
       eq(('\nE17: "'..funcs.fnamemodify('.', ':p:h')..'" is a directory'),
         redir_exec('write .'))
     end
@@ -108,7 +110,7 @@ describe(':write', function()
     funcs.setfperm(fname, 'r--------')
     eq('Vim(write):E505: "Xtest-functional-ex_cmds-write" is read-only (add ! to override)',
        exc_exec('write'))
-    if helpers.iswin() then
+    if iswin() then
       eq(0, os.execute('del /q/f ' .. fname))
       eq(0, os.execute('rd /q/s ' .. fname_bak))
     else
@@ -117,7 +119,7 @@ describe(':write', function()
     end
     write_file(fname_bak, 'TTYX')
     -- FIXME: exc_exec('write!') outputs 0 in Windows
-    if helpers.iswin() then return end
+    if iswin() then return end
     lfs.link(fname_bak .. ('/xxxxx'):rep(20), fname, true)
     eq('Vim(write):E166: Can\'t open linked file for writing',
        exc_exec('write!'))

test/functional/legacy/011_autocommands_spec.lua

@@ -17,9 +17,10 @@ local lfs = require('lfs')
 local clear, feed_command, expect, eq, neq, dedent, write_file, feed =
   helpers.clear, helpers.feed_command, helpers.expect, helpers.eq, helpers.neq,
   helpers.dedent, helpers.write_file, helpers.feed
+local iswin = helpers.iswin
 
 local function has_gzip()
-  local null = helpers.iswin() and 'nul' or '/dev/null'
+  local null = iswin() and 'nul' or '/dev/null'
   return os.execute('gzip --help >' .. null .. ' 2>&1') == 0
 end
 
@@ -59,7 +60,7 @@ describe('file reading, writing and bufnew and filter autocommands', function()
     os.remove('test.out')
   end)
 
-  if not has_gzip() then
+  if iswin() or not has_gzip() then
     pending('skipped (missing `gzip` utility)', function() end)
   else