Cert: Set log_path for each test suite

Currently the base log_path is the relative root of each run. Set it to
each test suite (class) instead, so they won't be overwritten. Also pull
logcat and btsnoop from device

Test: cert/run_cert_facade_only.sh and cert/run_device_cert.sh
Bug: 148147248
Change-Id: I4f1a4559fd6d84070cfd688a399bdbd46e26a5d7