patch 8.2.0533: tests using term_wait() can still be flaky

Problem:    Tests using term_wait() can still be flaky.
Solution:   Increase the wait time when rerunning a test. (James McCoy,
            closes #5899)  Halve the initial times to make tests run faster
            when there is no rerun.
diff --git a/src/testdir/test_timers.vim b/src/testdir/test_timers.vim
index 1a6391b..546df1f 100644
--- a/src/testdir/test_timers.vim
+++ b/src/testdir/test_timers.vim
@@ -398,9 +398,9 @@
   call WaitForAssert({-> assert_notequal('', term_getline(buf, 8))})
 
   " GC must not run during timer callback, which can make Vim crash.
-  call term_wait(buf, 100)
+  call TermWait(buf, 50)
   call term_sendkeys(buf, "\<CR>")
-  call term_wait(buf, 100)
+  call TermWait(buf, 50)
   call assert_equal('run', job_status(job))
 
   call term_sendkeys(buf, ":qall!\<CR>")