RFR: 8309934: Update GitHub Actions to use JDK 17 for building jtreg [v2]

[Christian Stein]

> Hi all,
> 
> This pull request contains a backport of commit [8aad881e](https://github.com/openjdk/jdk/commit/8aad881e803fddc26f45270f779ff0c0e5a095d8) from the [openjdk/jdk](https://git.openjdk.org/jdk) repository.
> 
> The commit being backported was authored by Christian Stein on 13 Jun 2023 and was reviewed by Erik Joelsson.
> 
> Thanks!

Christian Stein has updated the pull request incrementally with one additional commit since the last revision:

  Trigger GHA workflow run

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Changes:
  - all: https://git.openjdk.org/jdk21/pull/18/files
  - new: https://git.openjdk.org/jdk21/pull/18/files/ab75266e..f543006a

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk21&pr=18&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk21&pr=18&range=00-01

  Stats: 0 lines in 0 files changed: 0 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk21/pull/18.diff
  Fetch: git fetch https://git.openjdk.org/jdk21.git pull/18/head:pull/18

PR: https://git.openjdk.org/jdk21/pull/18