SOLR-16427: Enable error-prone ClassInitializationDeadlock rule

[malliaridis]

https://issues.apache.org/jira/browse/SOLR-16427

Description

With the ClassInitializationDeadlock rule error-prone checks for possible class initialization deadlocks. See error-prone documentation for details about the problem this rule is fixing.

Solution

Following the suggestions of error-prone, the possible deadlocks are resolved by introducing separate classes for constant fields.

You can review commits individually for a better overview.

This PR deprecates the classes in the old location and uses the new classes project-wide for partial backwards compatibility. This may break third-party / user code that reference the old classes. If we drop the need for backwards compatibility we can remove completely the deprecated classes and methods and solely update the CHANGES.txt by mentioning the new classes.

• Update CHANGES.txt before merge

Tests

Please describe the tests you've developed or run to confirm this patch implements the feature or solves the problem.

Checklist

Please review the following and check all that apply:

• I have reviewed the guidelines for How to Contribute and my code conforms to the standards described there to the best of my ability.
• [X ] I have created a Jira issue and added the issue ID to my pull request title.
• I have given Solr maintainers access to contribute to my PR branch. (optional but recommended, not available for branches on forks living under an organisation)
• I have developed this patch against the main branch.
• I have run ./gradlew check.
• I have added tests for my changes.
• I have added documentation for the Reference Guide