frameworks/base: creating separate files for ANRs traces based on debug flag

In case of multiple ANRs in different apps, we will get the traces for
the last ANR.
This patch will create one trace file for each application in case of ANR
and the filename would be traces_<app_name>_<date>.txt

Change-Id: Ib67d1961182938c797a9a3041fdf9a97b40ec14b