Lacros: Add vaapi_unittests to Lacros builder

VAAPI has been enabled on Lacros for a while. This CL adds vaapi unit
tests to the Lacros builder.

BUG=b:192563831
BUG=1425489

Change-Id: Id719f57a503b722ceec3c231e0e3b25c2fad1ae0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4347132


Commit-Queue: Pilar Molina Lopez <pmolinalopez@chromium.org>
Reviewed-by: Andres Calderon Jaramillo <andrescj@chromium.org>
Reviewed-by: Sven Zheng <svenzheng@chromium.org>
Reviewed-by: Ben Pastene <bpastene@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1118925}