[jdk17u-dev] RFR: 8308633: Increase precision of timestamps in g1 log

[Daniel Hu]

Clean backport. The change adds a digit of precision to g1 logs. Passes GHA. Affected gtest passes with the change and fails without.

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Commit messages:
 - Backport c23794f88270c121bf99fdf297fdfde53072e3b6

Changes: https://git.openjdk.org/jdk17u-dev/pull/4188/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=4188&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8308633
  Stats: 13 lines in 4 files changed: 3 ins; 0 del; 10 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/4188.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/4188/head:pull/4188

PR: https://git.openjdk.org/jdk17u-dev/pull/4188