Merge branch 'cc/perf-run-config'

* cc/perf-run-config:
  perf: store subsection results in "test-results/$GIT_PERF_SUBSECTION/"
  perf/run: show name of rev being built
  perf/run: add run_subsection()
  perf/run: update get_var_from_env_or_config() for subsections
  perf/run: add get_subsections()
  perf/run: add calls to get_var_from_env_or_config()
  perf/run: add GIT_PERF_DIRS_OR_REVS
  perf/run: add get_var_from_env_or_config()
  perf/run: add '--config' option to the 'run' script