patch 8.2.5112: gui test hangs on MS-Windows

Problem:    Gui test hangs on MS-Windows.
Solution:   Use "!start" to start Vim.
diff --git a/src/testdir/test_gui.vim b/src/testdir/test_gui.vim
index 954cf2a..373a0a2 100644
--- a/src/testdir/test_gui.vim
+++ b/src/testdir/test_gui.vim
@@ -1594,7 +1594,11 @@
     confirm qa
   END
   call writefile(lines, 'Xlines')
-  execute '!' .. GetVimCommand() .. ' -g -f --clean --gui-dialog-file Xdialog -S Xlines'
+  let prefix = '!'
+  if has('win32')
+    let prefix = '!start '
+  endif
+  execute prefix .. GetVimCommand() .. ' -g -f --clean --gui-dialog-file Xdialog -S Xlines'
 
   call WaitForAssert({-> assert_true(filereadable('Xdialog'))})
   call assert_match('Question: Save changes to "Xfile"?', readfile('Xdialog')->join('<NL>'))
diff --git a/src/version.c b/src/version.c
index a438340..66b03c3 100644
--- a/src/version.c
+++ b/src/version.c
@@ -735,6 +735,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    5112,
+/**/
     5111,
 /**/
     5110,