RFR: Merge jdk8u:master

[Andrew John Hughes]

Merge jdk8u345-b01

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Commit messages:
 - Merge jdk8u345-b01
 - 8290832: It is no longer possible to change "user.dir" in the JDK8
 - 8291568: Bump update version of OpenJDK: 8u345

The webrevs contain the adjustments done while merging with regards to each parent branch:
 - master: https://webrevs.openjdk.org/?repo=shenandoah-jdk8u&pr=22&range=00.0
 - jdk8u:master: https://webrevs.openjdk.org/?repo=shenandoah-jdk8u&pr=22&range=00.1

Changes: https://git.openjdk.org/shenandoah-jdk8u/pull/22/files
  Stats: 69 lines in 5 files changed: 0 ins; 65 del; 4 mod
  Patch: https://git.openjdk.org/shenandoah-jdk8u/pull/22.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah-jdk8u.git pull/22/head:pull/22

PR: https://git.openjdk.org/shenandoah-jdk8u/pull/22