am: Make unfreezeTemporarily() use ProcessRecordInternal

This change refactors the app freezer state management by moving
attributes such as `isFrozen()`, `isFreezeExempt()`, and
`shouldNotFreeze()` from `ProcessCachedOptimizerRecord` directly
into `ProcessRecordInternal`.

Additionally, the `processName` field is elevated from `ProcessRecord`
to `ProcessRecordInternal`.

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

Change-Id: Id9da2f66ff4a991112376ef926e3b53b0f8acf03