autotest: parametrize autoupdate suite name

This allows us to use arbitrary names for differentiating tests. It is
currently needed for autoupdate tests of paygen generated payloads.

BUG=chromium:263133
TEST=Control file generated correctly with both default + custom suite names

Change-Id: Id11532bba54e550b053a625196da466e96f454fe
Reviewed-on: https://gerrit.chromium.org/gerrit/64004
Commit-Queue: Gilad Arnold <garnold@chromium.org>
Reviewed-by: Gilad Arnold <garnold@chromium.org>
Tested-by: Gilad Arnold <garnold@chromium.org>
1 file changed