[pinpoint_cli] Fix get-csv for windows platforms
[pinpoint_cli] Fix get-csv for windows platforms

The filepath from where to read perf results depends on whether the
job was run on a windows or a posix platform. Make sure we use the
correct path.

Bug: catapult:#4594
Change-Id: I273ea74fd30035587677d2141825465a29eb683c
Reviewed-on: https://chromium-review.googlesource.com/c/1290692
Reviewed-by: Dave Tu <baa605d781958521249fdcf7bad76b01d943134a@chromium.org>
Commit-Queue: Juan Antonio Navarro Pérez <1649bb5e6b9eafe026580e338065dc64ba6b80b2@chromium.org>

catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult