PhoneWindowManager: honor disabled screen-on reclaim setting

[CeRRiLLo89]

Summary

Re-read SCREEN_ON_MEMORY_RECLAIM immediately before executing the delayed
screen-on memory reclaim.

Problem

PhoneWindowManager schedules mMemoryOpt from the cached
mScreenOnReclaim value and executes the callback 1250 ms later.

The callback previously called releaseMemoryAtScreenOn() without checking
the current setting again.

On raphael with crDroid Android 16, screen-on reclaim was reproduced while:

• the active user was 0;
• screen_on_memory_reclaim was 0;
• the exact-build mitigation module was disabled;
• the original services.jar was active.

One controlled screen-on cycle produced the reclaim log 1251 ms after wake
and killed 25 cached processes, including the Android Auto car process.

The exact reason for the stale cached state has not been proven. It may involve
setting-observer timing or cross-thread visibility.

Change

• Centralize the current setting lookup.
• Mark the cached flag volatile because it is updated and read from different
  execution contexts.
• Re-read the setting before the delayed callback releases memory.
• Preserve the existing reclaim behavior when the setting is enabled.
• Expose the delayed callback for unit testing with @VisibleForTesting.

This does not modify:

• LMKD
• ZRAM
• Cached App Freezer
• the reclaim interval
• the reclaim parameters
• system_server garbage collection

Tests

Added unit coverage verifying that:

• a disabled setting prevents the delayed callback from calling
  releaseMemory();
• an enabled setting preserves the existing reclaim call.

The ActivityManager call is stubbed so the tests do not perform a real reclaim.

The tests have been added but have not been executed locally because a full
Android framework build environment is not currently available.

Expected test command:

atest WmTests:PhoneWindowManagerTests

Device context

Device: Xiaomi Mi 9T Pro / Redmi K20 Pro (raphael)

Build: crDroid Android 16 v12.11-20260623

The exact-build KernelSU mitigation remains enabled until a ROM build
containing this source change is available for controlled validation.

Validation status

• Controlled device reproduction: completed.
• Source review: completed.
• Source compilation: pending.
• Unit test execution: pending.
• Device validation with a source build: pending.