Problem:    A user command with try/catch may not catch an expression error.
Solution:   When an expression fails check for following "|". (closes #7469)

Problem:    Vim9: Cannot use "fina" for "finally". (Naruhiko Nishino)
Solution:   Specifically check for "fina". (closes #7020)

Problem:    assert_fails() checks the last error message.
Solution:   Check the first error, it is more relevant.  Fix all the tests
            that rely on the old behavior.

Problem:    various code is not properly tested.
Solution:   Add more tests. (Yegappan Lakshmanan, closes #5871)

Problem:    Insufficient testing for exception handling and the "attention"
            prompt.
Solution:   Add test cases. (Yegappan Lakshmanan, closes #5681)

Problem:    Various Ex commands not sufficiently tested.
Solution:   Add more test cases. (Yegappan Lakshmanan, closes #5673)

Problem:    Get E685 and E931 if buffer reload is interrupted.
Solution:   Do not abort deleting a dummy buffer. (closes #5361)

Problem:    Some tests are still in old style.
Solution:   Change a few tests to new style. (Yegappan Lakshmanan)