Split dumpsys into critical and non-critical sections.

Order in which we report stats in bugreport can disrupt cpu and memory
stats. This CL sorts the bugreport process
from least impactful to most impactful to try and keep the
system stats as close to its initial state as possible throughout the BR (eg.
things like dumpsys meminfo should run before dumping thread stacks)

BUG: 26639621
Change-Id: I29dccfd423d83a6a69b7e025d45cb9cebfc41cc4