psc: Migrate ProcessRecord freeze APIs to ProcessRecordInternal

The `shouldNotFreeze()`, `setShouldNotFreeze()`, and
`shouldNotFreezeReason()` methods are now abstract methods in
`ProcessRecordInternal`. `ProcessRecord` implements these methods by
delegating to its `ProcessCachedOptimizerRecord` (`mOptRecord`).

This change unblocks `OomAdjuster.computeServiceHostOomAdjLSP()` to use
`ProcessRecordInternal` for its `client` parameter.

Bug: 425766486
Test: m services.core
Test: atest MockingOomAdjusterTests OomAdjusterTests
Test: atest FrameworksServicesTestsRavenwood_ProcessStateController
Flag: EXEMPT pure refactor

Change-Id: If0f0bdae6f7770586f8b1575fc10e3d3ce7d6f0f