Feat(SystemClock): Added PreciseClock implementation to the system clock class, for the benefit of Java 8 users.

[jaykataria1111]

Straight forward change to override the behavior of System Clock, to implement the Precise Clock interface, for the benefit of Java 8 users. The PR is for issue #3198

Checklist

• Base your changes on 2.x branch if you are targeting Log4j 2; use main otherwise
• ./mvnw verify succeeds (if it fails due to code formatting issues reported by Spotless, simply run ./mvnw spotless:apply and retry)
• Non-trivial changes contain an entry file in the src/changelog/.2.x.x directory
• Tests for the changes are provided
• Commits are signed (optional, but highly recommended)

[github-actions]

Job	Requested goals	Build Tool Version	Build Outcome	Build Scan®
build-macos-latest	clean install	3.9.8	❌
build-ubuntu-latest	clean install	3.9.8	❌
build-windows-latest	clean install	3.9.8	❌

Generated by gradle/develocity-actions

[ppkarwasz]

The build failure is due to the 2.24.2 release being published (BND checks your code against 2.24.2 now, instead of 2.24.1 before).

Please, rebase.