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_conceal.vim b/src/testdir/test_conceal.vim
index af0c3b8..bf942b7 100644
--- a/src/testdir/test_conceal.vim
+++ b/src/testdir/test_conceal.vim
@@ -147,7 +147,7 @@
   call VerifyScreenDump(buf, 'Test_conceal_resize_01', {})
 
   call win_execute(buf->win_findbuf()[0], 'wincmd +')
-  call term_wait(buf)
+  call TermWait(buf)
   call VerifyScreenDump(buf, 'Test_conceal_resize_02', {})
 
   " clean up