patch 8.2.0534: client-server test fails under valgrind

Problem:    Client-server test fails under valgrind.
Solution:   Use WaitForAssert().

Author: brammool

src/testdir/test_clientserver.vim

@@ -129,7 +129,7 @@ func Test_client_server()
 
     " Edit files in separate tab pages
     call system(cmd .. ' --remote-tab Xfile1 Xfile2 Xfile3')
-    call assert_equal('3', remote_expr(name, 'tabpagenr("$")'))
+    call WaitForAssert({-> assert_equal('3', remote_expr(name, 'tabpagenr("$")'))})
     call assert_equal('Xfile2', remote_expr(name, 'bufname(tabpagebuflist(2)[0])'))
     eval name->remote_send(":%bw!\<CR>")
 

src/version.c

@@ -738,6 +738,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    534,
 /**/
     533,
 /**/