patch 8.2.3553: xxd test fails on MS-Windows

Problem:    Xxd test fails on MS-Windows.
Solution:   Split shell command in two.
diff --git a/src/testdir/test_xxd.vim b/src/testdir/test_xxd.vim
index fec0122..7768f90 100644
--- a/src/testdir/test_xxd.vim
+++ b/src/testdir/test_xxd.vim
@@ -214,31 +214,38 @@
 endfunc
 
 func Test_xxd_patch()
-  let cmd = 'silent !' .. s:xxd_cmd .. ' -r Xxxdin Xxxdfile; ' .. s:xxd_cmd .. ' -g1 Xxxdfile > Xxxdout'
+  let cmd1 = 'silent !' .. s:xxd_cmd .. ' -r Xxxdin Xxxdfile'
+  let cmd2 = 'silent !' .. s:xxd_cmd .. ' -g1 Xxxdfile > Xxxdout'
   call writefile(["2: 41 41", "8: 42 42"], 'Xxxdin')
   call writefile(['::::::::'], 'Xxxdfile')
-  exe cmd
+  exe cmd1
+  exe cmd2
   call assert_equal(['00000000: 3a 3a 41 41 3a 3a 3a 3a 42 42                    ::AA::::BB'], readfile('Xxxdout'))
 
   call writefile(["2: 43 43 ", "8: 44 44"], 'Xxxdin')
-  exe cmd
+  exe cmd1
+  exe cmd2
   call assert_equal(['00000000: 3a 3a 43 43 3a 3a 3a 3a 44 44                    ::CC::::DD'], readfile('Xxxdout'))
 
   call writefile(["2: 45 45  ", "8: 46 46"], 'Xxxdin')
-  exe cmd
+  exe cmd1
+  exe cmd2
   call assert_equal(['00000000: 3a 3a 45 45 3a 3a 3a 3a 46 46                    ::EE::::FF'], readfile('Xxxdout'))
   
   call writefile(["2: 41 41", "08: 42 42"], 'Xxxdin')
   call writefile(['::::::::'], 'Xxxdfile')
-  exe cmd
+  exe cmd1
+  exe cmd2
   call assert_equal(['00000000: 3a 3a 41 41 3a 3a 3a 3a 42 42                    ::AA::::BB'], readfile('Xxxdout'))
 
   call writefile(["2: 43 43 ", "09: 44 44"], 'Xxxdin')
-  exe cmd
+  exe cmd1
+  exe cmd2
   call assert_equal(['00000000: 3a 3a 43 43 3a 3a 3a 3a 42 44 44                 ::CC::::BDD'], readfile('Xxxdout'))
 
   call writefile(["2: 45 45  ", "0a: 46 46"], 'Xxxdin')
-  exe cmd
+  exe cmd1
+  exe cmd2
   call assert_equal(['00000000: 3a 3a 45 45 3a 3a 3a 3a 42 44 46 46              ::EE::::BDFF'], readfile('Xxxdout'))
   
   call delete('Xxxdin')
diff --git a/src/version.c b/src/version.c
index 0143761..8babe70 100644
--- a/src/version.c
+++ b/src/version.c
@@ -758,6 +758,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    3553,
+/**/
     3552,
 /**/
     3551,