[Fuchsia] Remove system logging logic from RunPackage()

Previously runner scripts implemented system logs collection in two
enabled by default, but could be turned off with --exclude-system-logs.
(2) was disabled by default, but can be turned on with
--system-log-file. (2) is enabled on the bots now. This CL removes (1)
in order to remove noice from runner script output and to simplify code.
When necessary --system-log-file=- flag can be used to get the previous
behavior.

places: (1) in RunPackage, and (2) in Target implementations. (1) was
Change-Id: I787ff4d8ac54f5c0cd13d0e9d8a71aad05cdd45c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1674668
Commit-Queue: Sergey Ulanov <sergeyu@chromium.org>
Commit-Queue: Kevin Marshall <kmarshall@chromium.org>
Reviewed-by: Kevin Marshall <kmarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#672180}
2 files changed