crosperf: remove uses of numpy

New in python3 (compared to python2) is a `statistics` module, which
provides all of the functionality we wanted from numpy here. Use that
instead.

BUG=chromium:980719
TEST=Unittests

Change-Id: I5eaa53744142c402d1e71d6b867e434940d41aec
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/2353422
Reviewed-by: Tiancong Wang <tcwang@google.com>
Tested-by: George Burgess <gbiv@chromium.org>
1 file changed