RFR: 8204256: improve jlink error message to report unsupported class file format [v2]

[Mandy Chung]

On Fri, 2 Oct 2020 09:34:59 GMT, Alan Bateman <alanb at openjdk.org> wrote:

>> Given that linking with JMODs of an unsupported class file version is rare case,
>> it's not a bad choice to go with this simplest solution printing the stack trace.
>
> What if we removed the handling of specific exceptions from L278-L285 so that the special handling is limited to
> BadArgs? If anything other than BadArgs is throw then it can print the exception to log output along with the cause (if
> not null). No objection. That might avoid the tool emitting a "scary" stack trace when an error occurs.

I think for `ResolutionException` and IAE (and possibly `PluginException`), the exception message should be helpful
enough to correct for example user-errors and that's why this special catch block.

Having another look, I think `FindException` may just fall into the last `Throwable` handler.   The new catch block may
not be needed.

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PR: https://git.openjdk.java.net/jdk/pull/409