RFR: 8212: Update trunk to 9.1.0 [v2]

[Alex Macdonald]

On Tue, 26 Mar 2024 11:44:39 GMT, Marcus Hirt <hirt at openjdk.org> wrote:

>> Also EA splash and minor versioning fixes.
>
> Marcus Hirt has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Copyright updates

Marked as reviewed by aptmac (Reviewer).

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PR Review: https://git.openjdk.org/jmc/pull/558#pullrequestreview-1960673185