[crosperf] Add more tests for results_report.
With this patch, all of the classes in results_report have tests. The
tests aren't overly extensive, but we can always improve on them later.
This also includes a few small cleanups of parts of machine_manager, and
results_report.
BUG=None
TEST=./run_tests.sh
Change-Id: I9613579d4f8c1079b452e1a0a2edf47b189ac1cd
Reviewed-on: https://chrome-internal-review.googlesource.com/268057
Commit-Ready: George Burgess <gbiv@google.com>
Tested-by: George Burgess <gbiv@google.com>
Reviewed-by: Caroline Tice <cmtice@google.com>
3 files changed
