RFR: 8212: Update trunk to 9.1.0 [v2]

[Marcus Hirt]

> 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

-------------

Changes:
  - all: https://git.openjdk.org/jmc/pull/558/files
  - new: https://git.openjdk.org/jmc/pull/558/files/18311642..dd157427

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jmc&pr=558&range=01
 - incr: https://webrevs.openjdk.org/?repo=jmc&pr=558&range=00-01

  Stats: 10 lines in 6 files changed: 0 ins; 0 del; 10 mod
  Patch: https://git.openjdk.org/jmc/pull/558.diff
  Fetch: git fetch https://git.openjdk.org/jmc.git pull/558/head:pull/558

PR: https://git.openjdk.org/jmc/pull/558