RFR: 8302838: jabswitch main() should avoid calling exit explicitly [v2]

[Sergey Bylokhov]

On Tue, 21 Feb 2023 17:01:02 GMT, Julian Waters <jwaters at openjdk.org> wrote:

>> In jabswitch, main is defined as `void main()`, which requires an explicit exit call whenever an error occurs, and extra error checking code on our part. Visual C++ will automatically convert all instances of `void main()` to return 0 in all cases anyway, and there isn't anything gained from using this custom signature when the same can be achieved by simply returning the error value normally, so I propose we simply change it to the regular `int main` signature
>
> Julian Waters has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains two additional commits since the last revision:
> 
>  - Merge branch 'openjdk:master' into patch-8
>  - jabswitch.cpp

Marked as reviewed by serb (Reviewer).

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PR: https://git.openjdk.org/jdk/pull/12650