cros-test: specify -ephemeraldevserver=false to tast

Specify -ephemeraldevserver=false to tast when there is cache server is
specified.

BUG=b:301296858
TEST=CQ

Change-Id: I967492927b34b0115d54d0146b83b7fe071e4937
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/4874324
Reviewed-by: Gowri Denduluri <gowriden@google.com>
Reviewed-by: Derek Beckett <dbeckett@chromium.org>
Commit-Queue: Seewai Fu <seewaifu@google.com>
Tested-by: Seewai Fu <seewaifu@google.com>
1 file changed