Add cache for PackageManager.getPackageUid to improvement performance

Context: `PackageManager.getPackageUid` is IPC which could be slow. Add a map in BatteryDiffEntry to cache the data. The cache lifecycle would be the same as other cache in BatteryDiffEntry.

Test: manual
Bug: 304439237
Fix: 304439237
Change-Id: I98d9c8cfee24dd43e9a4037b1b61c8353bf1bcea
2 files changed