test: reduce sleep for file timestamp change (#28196)

Now that Nvim always supports nanotime, sleeping for some milliseconds
is enough.

test/functional/api/keymap_spec.lua

@@ -738,7 +738,7 @@ describe('nvim_set_keymap, nvim_del_keymap', function()
     end
   end
 
-  it('can set mappings containing literal keycodes', function()
+  it('can set mappings containing C0 control codes', function()
     api.nvim_set_keymap('n', '\n\r\n', 'rhs', {})
     local expected = generate_mapargs('n', '<NL><CR><NL>', 'rhs')
     eq(expected, get_mapargs('n', '<NL><CR><NL>'))

test/functional/shada/marks_spec.lua

@@ -163,17 +163,17 @@ describe('ShaDa support code', function()
     eq({ 2, 0 }, api.nvim_win_get_cursor(0))
   end)
 
-  it('is able to dump and restore jump list with different times (slow!)', function()
+  it('is able to dump and restore jump list with different times', function()
     nvim_command('edit ' .. testfilename_2)
-    nvim_command('sleep 2')
+    nvim_command('sleep 10m')
     nvim_command('normal! G')
-    nvim_command('sleep 2')
+    nvim_command('sleep 10m')
     nvim_command('normal! gg')
-    nvim_command('sleep 2')
+    nvim_command('sleep 10m')
     nvim_command('edit ' .. testfilename)
-    nvim_command('sleep 2')
+    nvim_command('sleep 10m')
     nvim_command('normal! G')
-    nvim_command('sleep 2')
+    nvim_command('sleep 10m')
     nvim_command('normal! gg')
     expect_exit(nvim_command, 'qall')
     reset()

test/functional/ui/input_spec.lua

@@ -336,8 +336,8 @@ describe('input non-printable chars', function()
       "Xtest-overwrite" [noeol] 1L, 6B                            |
     ]])
 
-    -- The timestamp is in second resolution, wait two seconds to be sure.
-    screen:sleep(2000)
+    -- Wait for some time so that the timestamp changes.
+    vim.uv.sleep(10)
     write_file('Xtest-overwrite', [[smurf]])
     feed_command('w')
     screen:expect([[