patch 8.2.0382: some tests fail when run under valgrind

Problem:    Some tests fail when run under valgrind.
Solution:   Increase timeouts.
diff --git a/src/testdir/test_debugger.vim b/src/testdir/test_debugger.vim
index c541802..8ba3998 100644
--- a/src/testdir/test_debugger.vim
+++ b/src/testdir/test_debugger.vim
@@ -8,7 +8,7 @@
 " If the expected output argument is supplied, then check for it.
 func RunDbgCmd(buf, cmd, ...)
   call term_sendkeys(a:buf, a:cmd . "\r")
-  call term_wait(a:buf)
+  call term_wait(a:buf, 20)
 
   if a:0 != 0
     " Verify the expected output