patch 8.2.2708: test sometimes fails waiting for shell in terminal

Problem:    Test sometimes fails waiting for shell in terminal.
Solution:   Use WaitForAssert() so we can see the actual job status.  Use
            Run_shell_in_terminal().

src/testdir/term_util.vim

@@ -23,7 +23,7 @@ endif
 func StopShellInTerminal(buf)
   call term_sendkeys(a:buf, "exit\r")
   let job = term_getjob(a:buf)
-  call WaitFor({-> job_status(job) == "dead"})
+  call WaitForAssert({-> assert_equal("dead", job_status(job))})
 endfunc
 
 " Wrapper around term_wait() to allow more time for re-runs of flaky tests
@@ -160,7 +160,7 @@ endfunc
 " number.
 func Run_shell_in_terminal(options)
   if has('win32')
-    let buf = term_start([&shell,'/k'], a:options)
+    let buf = term_start([&shell, '/k'], a:options)
   else
     let buf = term_start(&shell, a:options)
   endif

src/testdir/test_mksession.vim

@@ -392,7 +392,7 @@ endfunc
 func Test_mksession_terminal_no_restore_funcarg()
   CheckFeature terminal
 
-  call term_start(&shell, {'norestore': 1})
+  let buf = Run_shell_in_terminal({'norestore': 1})
   mksession! Xtest_mks.out
   let lines = readfile('Xtest_mks.out')
   let term_cmd = ''
@@ -402,7 +402,7 @@ func Test_mksession_terminal_no_restore_funcarg()
     endif
   endfor
 
-  call StopShellInTerminal(bufnr('%'))
+  call StopShellInTerminal(buf)
   call delete('Xtest_mks.out')
 endfunc
 

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2708,
 /**/
     2707,
 /**/