Revert "Disable lacros_chrome_browsertests for device."

This reverts commit a4a8af90.

Reason for revert: Broke chromeos-amd64-generic-lacros-dbg
https://ci.chromium.org/p/chromium/builders/ci/chromeos-amd64-generic-lacros-dbg/129

Original change's description:
> Disable lacros_chrome_browsertests for device.
> 
> These tests only run on Linux, not on ChromeOS devices.
> 
> Change-Id: If22d19f0cdcb95efd412d7c099df05361413350f
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2419007
> Commit-Queue: Erik Chen <erikchen@chromium.org>
> Commit-Queue: Avi Drissman <avi@chromium.org>
> Auto-Submit: Erik Chen <erikchen@chromium.org>
> Reviewed-by: Avi Drissman <avi@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#808521}

TBR=avi@chromium.org,erikchen@chromium.org

Change-Id: I6ffb195890b15821d53a93972b9380e52652f8af
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2419148Reviewed-by: Fabrice de Gans-Riberi <fdegans@chromium.org>
Commit-Queue: Fabrice de Gans-Riberi <fdegans@chromium.org>
Cr-Commit-Position: refs/heads/master@{#808556}

chrome/test/BUILD.gn

@@ -4,7 +4,6 @@
 
 import("//build/config/buildflags_paint_preview.gni")
 import("//build/config/chrome_build.gni")
-import("//build/config/chromeos/args.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
@@ -3046,10 +3045,9 @@ if (!is_android) {
   }
 }
 
-if (chromeos_is_browser_only && !is_chromeos_device) {
+if (chromeos_is_browser_only) {
   # This test target is intended for lacros chrome specific tests that depend
   # on crosapi, for generic tests, please use 'browser_tests' target instead.
-  # These tests only run on Linux.
   test("lacros_chrome_browsertests") {
     use_xvfb = use_xvfb_in_this_config