fio_util: Parse json output instead of terse output

Currently fio_runner uses terse output from fio to parse
fio result there are several drawback for this approach.
1. We must hard-coded the output format of fio which mean that
we need to modify code every time fio add new feature.
2. We can not efficiently determine type of each result by
looking at fio result except hard-coding it.
3. We con not efiiciently filter out useless report. Such as
read statistics in write only work load.

This patch runs fio using json output mode and create new
parser to parse it using python json library.

CQ-DEPEND=CL:205521
BUG=chromium:387142
TEST=Run with test_that

Change-Id: I052d58fd69472de29548d100bdbd4400065fb070
Reviewed-on: https://chromium-review.googlesource.com/205430
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Commit-Queue: Gwendal Grignou <gwendal@chromium.org>
Tested-by: Gwendal Grignou <gwendal@chromium.org>
3 files changed