lisa.trace: Use lisa._assets.get_bin() for trace-cmd
lisa.trace: Use lisa._assets.get_bin() for trace-cmd

FEATURE

Use the trace-cmd binary shipped by LISA to improve reproducibility and
for when lisa is installed from PyPI.

It is still possible to make LISA prefer the system binary by setting
LISA_USE_SYSTEM_BIN=1 environment variable.

ARM-software/lisa,ARM-software/lisa,ARM-software/lisa,ARM-software/lisa