update preloaded-classes

Remove some preloaded-classes and fix typo for deleting log messages
as the followings during booting.

W/Zygote  (  163): Class not found for preloading: android.bluetooth.
BluetoothAudioGateway
W/Zygote  (  163): Class not found for preloading: android.bluetooth.
HeadsetBase
W/Zygote  (  163): Class not found for preloading: undroid.content.Ab
stractThreadedSyncAdapter$SyncThread

Change-Id: Id02e0cccaeb150f48e12d67b2d691df828842e4c
core/jni/android/graphics: Cache copy of pre-scaled Bitmaps

Caching some pre-scaled Bitmap objects allows for optimizing later
scaling operations to reduce memory pressure.

CRs-fixed: 451681

Change-Id: Id4341e75911074ff9f565b2d386ccad8f3a223e8
am: Allow more hidden apps on devices with lots of RAM

 * If more than 1.5GB is present, allow up to 40 hidden apps.
 * Number is somewhat arbitrary, but was found to work well on D2.
 * Also look at the sys.mem.max_hidden_apps value if given.

Change-Id: I2d3cf6e0dad1bc0b482cc37bf9c61ed2f2b4be51