Problem:    Vim9: not enough tests.
Solution:   Add tests for :try/:catch and :redir. Add missing type check.

Problem:    Vim9: inconsistent error for using function().
Solution:   Use a runtime type check for the result of function().
            (closes #8492)

Problem:    Vim9: not enough tests.
Solution:   Run more expression tests also with Vim9. Fix an uncovered
            problem.

Problem:    Illegal memory access when displaying a blob.
Solution:   Append a NUL at the end. (Yegappan Lakshmanan, closes #9372)

Problem:    Vim9: inconsistent arguments for test functions.
Solution:   When :def function and script have different arguments use a list
            with two items instead of a separate function.

Problem:    Vim9: not enough tests.
Solution:   Run more existing tests for Vim9 script.

Problem:    Vim9: not enough tests.
Solution:   Also run existing tests for Vim9 script.  Make errors more
            consistent.

Problem:    Vim9: overhead when comparing string, dict or function.
Solution:   Call the intented compare function directly.  Refactor to avoid
            duplicated code.

Problem:    Illegal memory access when displaying a partial.
Solution:   Terminate the string with a NUL. (closes #9371)

Problem:    Functions implementing reduce and map are too long.
Solution:   Use a function for each type of value.  Add a few more test cases
            and add to the help. (Yegappan Lakshmanan, closes #9370)