Reduce lock contention in the package manager dump

Applications frequently anr while the bugreport is capturing.
The problem is relevant to the package manager held the lock
contention long time in its dump. This patch removes the long
lock in the dump. Instead, it adds locks to each dump section.
A new `dump` function in the ComputerEngine is added also. The
sections which could be dumped withoud a lock are moved to it.

Bug: 178304105
Test: adb bugreport
Change-Id: Id3020ce335b81d79a1ce7ecb17d5a6cc1e428560