Fix 2660488: Add LockScreen/InCallScreen resources to preloads

This adds the base SlidinTab drawable resources shared by
InCallScreen and LockScreen into the zygote process. It should
save approximately 375kB (mdpi) and 825kB (hdpi) of RAM by
sharing resource between the LockScreen and InCallScreen.

Change-Id: I05bcafa894ed27d419b171ad5041bd83134461f7