scripts: gen_gcov_files.py: Added python script to parse uart dump

This script will parse the serial console log file and create the
required gcda files.

Usage:
python3 ${ZEPHYR_BASE}/scripts/gen_gcov_files.py -i console_output.log
Add -v for verbose.

Signed-off-by: Adithya Baglody <adithya.nagaraj.baglody@intel.com>
Signed-off-by: Anas Nashif <anas.nashif@intel.com>