frameworks/base: add app launch timeline instrumentation

Displayed Activity is often being used to measure application
launch times. However Displayed Activity only accounts for a
subset of the app launch. This additional instrumentation will
allow for more accurate measurements of applications launch
times.

ActivityManager: Update timeline debug statements
Update the timeline debug messages so that
'ActivityManager' is not used as the tag in log
messages as it interferes with some CTS tests.
CRs-fixed: 628703

This commit combines the changes from KK gerrit 668250 & 543988

Change-Id: I0af42520dc30d89a910e60aebdddf0c4fdd32b3e