[V3] Task tracer converter

Usage: python task_tracer_converter.py -i task_tracer.logcat [-c] [-p] [-w] [-o task_tracer_data.json]

The log format is changed a little bit.
- Discard the log type CREATE.
- Rename START as BEGIN.

log type:
0: DISPATCH
1: BEGIN
2: END
3: LABEL
4: VTABLE