RFR: 7903431: Update GitHub Actions workflow

[Christian Stein]

Update workflow to use `actions/checkout at v3` and set up latest Oracle's JDK 17 to build `jtreg`.

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Commit messages:
 - Use latest JDK 17 to build JTReg
 - Update `actions/checkout` to use `v3`

Changes: https://git.openjdk.org/jtreg/pull/148/files
 Webrev: https://webrevs.openjdk.org/?repo=jtreg&pr=148&range=00
  Issue: https://bugs.openjdk.org/browse/CODETOOLS-7903431
  Stats: 10 lines in 1 file changed: 6 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jtreg/pull/148.diff
  Fetch: git fetch https://git.openjdk.org/jtreg pull/148/head:pull/148

PR: https://git.openjdk.org/jtreg/pull/148