RFR: 8267636: Bump minimum boot jdk to JDK 17

[Mikael Vidstedt]

With the JDK 17 GA out it's time to bump the minimum boot JDK version for mainline/JDK 18.

Testing: tier1-5, GHA builds

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Commit messages:
 - 8267636: Bump minimum boot jdk to JDK 17

Changes: https://git.openjdk.java.net/jdk/pull/5639/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5639&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8267636
  Stats: 23 lines in 3 files changed: 0 ins; 9 del; 14 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5639.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5639/head:pull/5639

PR: https://git.openjdk.java.net/jdk/pull/5639