RFR: 6914: Fix windows check formatting script [v2]

[Marcus Hirt]

On Sat, 3 Oct 2020 08:19:43 GMT, Jean-Philippe Bempel <github.com+4610701+jpbempel at openjdk.org> wrote:

>> because mvn is itself a script we need to call with call command
>> to get control back to the main script
>
> Jean-Philippe Bempel has updated the pull request incrementally with one additional commit since the last revision:
> 
>   fail fast on calls

Would you perhaps want different fail codes for different fails?

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Marked as reviewed by hirt (Lead).

PR: https://git.openjdk.java.net/jmc/pull/114