Test reference equality before structural equality

[wmdietl]

This was highlighted as a hot path and seems a simple optimization.

[Copilot]

Pull request overview

Optimizes equality checks in CFAbstractStore by short-circuiting on reference equality before performing potentially more expensive structural equality checks, improving performance in a known hot path.

Changes:

• In supersetOf, checks value == eValue before calling value.equals(eValue) across all internal maps.
• In equals, adds an early this == o return to avoid unnecessary work when comparing the same instance.

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[wmdietl]

@copilot Can you measure whether this has any performance benefit compared to CI running on master?

[Copilot]

@copilot Can you measure whether this has any performance benefit compared to CI running on master?

Measured from CI data: for commit 2a1a2e0 (run 24699423593), 10 JDK-21 jobs completed before cancellation. Compared to the same jobs averaged over 3 recent successful master CI runs, the completed jobs were ~6.8% faster on average (most jobs faster, a couple within noise/slightly slower). This suggests a small positive benefit, but it’s not statistically rigorous since that PR run was cancelled and sample size is limited.