NO PARTIAL RERUN: Do not return recycled bitmaps

There's also no need to offload WallpaperManager#forgetLoadedBitmap
because Bitmap#recycle is asynchronous - and the whole method is
synchronized.

Fixes 77597550
Test: atest cts/tests/framework/base/activitymanager/src/android/server/am/ActivityManagerMultiDisplayTests.java

Change-Id: I88014e21bd05e10c2f524393bb637596708e4e63