patch 8.2.4809: various things no6 properly tested

Problem:    Various things no6 properly tested.
Solution:   Add various test cases. (Yegappan Lakshmanan, closes #10259)
diff --git a/src/testdir/test_listdict.vim b/src/testdir/test_listdict.vim
index 38eb338..1a6a1d0 100644
--- a/src/testdir/test_listdict.vim
+++ b/src/testdir/test_listdict.vim
@@ -1017,6 +1017,7 @@
 
   call assert_fails("call reduce([], { acc, val -> acc + val })", 'E998: Reduce of an empty List with no initial value')
   call assert_fails("call reduce(0z, { acc, val -> acc + val })", 'E998: Reduce of an empty Blob with no initial value')
+  call assert_fails("call reduce(test_null_blob(), { acc, val -> acc + val })", 'E998: Reduce of an empty Blob with no initial value')
   call assert_fails("call reduce('', { acc, val -> acc + val })", 'E998: Reduce of an empty String with no initial value')
   call assert_fails("call reduce(test_null_string(), { acc, val -> acc + val })", 'E998: Reduce of an empty String with no initial value')
 
@@ -1034,8 +1035,8 @@
   call assert_fails("call reduce('', { acc, val -> acc + val }, 0.1)", 'E1253:')
   call assert_fails("call reduce('', { acc, val -> acc + val }, function('tr'))", 'E1253:')
   call assert_fails("call reduce('abc', { a, v -> a10}, '')", 'E121:')
-  call assert_fails("call reduce(0z01, { a, v -> a10}, 1)", 'E121:')
-  call assert_fails("call reduce([1], { a, v -> a10}, '')", 'E121:')
+  call assert_fails("call reduce(0z0102, { a, v -> a10}, 1)", 'E121:')
+  call assert_fails("call reduce([1, 2], { a, v -> a10}, '')", 'E121:')
 
   let g:lut = [1, 2, 3, 4]
   func EvilRemove()