change execution mode for gen_icache_buster.py
change execution mode for gen_icache_buster.py

mbrukman/oldisim,GoogleCloudPlatform/oldisim,GoogleCloudPlatform/oldisim,mbrukman/oldisim,mbrukman/oldisim,mbrukman/oldisim,GoogleCloudPlatform/oldisim,GoogleCloudPlatform/oldisim