Revert "BootMessage: show more info in boot dialog"

This reverts commit e0837e1a2979d6fdabe99ce6e1708c1ac3ae607f.
[1/2] Speed up booting on multicore devices.

1. Add multithreading support to Installer/installd.
2. Parallelize package scanning.
3. Parallelize boot dexopt.

PS2: fix build

Change-Id: Id42b2bf4a737f93f9ecd9b5819344adbb735f0fb