Lacros: Refactor Lacros Tast tests

Support has been added for Lacros VM/Device tests to specify testing
args at runtime instead of at build time, so this CL refactors the
Lacros gn targets and test specs to use the new design.

Bug: 1195415
Change-Id: I35610267149dc1bd5e80f46d50ecf1c2c90caed7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2842505
Commit-Queue: Yuke Liao <liaoyuke@chromium.org>
Reviewed-by: Ben Pastene <bpastene@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@google.com>
Cr-Commit-Position: refs/heads/master@{#874869}
GitOrigin-RevId: 158660a1fe5580eea1933def9abc89d1873639d6
7 files changed