patch 8.2.0346: Vim9: finding common list type not tested

Problem:    Vim9: finding common list type not tested.
Solution:   Add more tests.  Fix listing function.  Fix overwriting type.
diff --git a/src/testdir/runtest.vim b/src/testdir/runtest.vim
index f0cc1ab..d8a1cf7 100644
--- a/src/testdir/runtest.vim
+++ b/src/testdir/runtest.vim
@@ -386,7 +386,7 @@
 redir @q
 silent function /^Test_
 redir END
-let s:tests = split(substitute(@q, 'function \(\k*()\)', '\1', 'g'))
+let s:tests = split(substitute(@q, '\(function\|def\) \(\k*()\)', '\2', 'g'))
 
 " If there is an extra argument filter the function names against it.
 if argc() > 1