LUCENE-10182: Be specific about which sizeOf() is called

[stefanvodita]

Description

Improve on TestRamUsageEstimator.testStaticOverloads's use of RamUsageTester.sizeOf for all calls to sizeOf.

Solution

Remove static import for RamUsageTester.sizeOf, and instead use RamUsageTester.sizeOf and RamUsageEstimator.sizeOf explicitly, when appropriate.

Tests

This code change is for one of the tests.

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.
• I have created a Jira issue and added the issue ID to my pull request title.
• I have given Lucene maintainers access to contribute to my PR branch. (optional but recommended)
• I have developed this patch against the main branch.
• I have run ./gradlew check.