[lacros] Enable also_build_ash_chrome on linux-lacros-rel

This CL enables also_build_ash_chrome gn arg on linux-lacros-rel to
support building both lacros chrome and ash-chrome inside the same
checkout.

Bug: 1129223
Change-Id: Ic549cd1c00ca2830314b4e8fd8e7fb700dc59b25
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2487696Reviewed-by: Erik Staab <estaab@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@google.com>
Commit-Queue: Yuke Liao <liaoyuke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#819130}

tools/mb/mb_config.pyl

@@ -2075,7 +2075,7 @@
     ],
 
     'lacros_on_linux_release_trybot': [
-      'lacros_on_linux', 'release_trybot',
+      'lacros_on_linux', 'release_trybot', 'also_build_ash_chrome',
     ],
 
     'libfuzzer_asan_debug_bot': [
@@ -2860,6 +2860,10 @@
       'gn_args': 'use_ozone=true ozone_platform_wayland=true ozone_platform="wayland" use_gtk=false chromeos_is_browser_only=true'
     },
 
+    'also_build_ash_chrome': {
+      'gn_args': 'also_build_ash_chrome=true',
+    },
+
     'libfuzzer': { 'gn_args': 'use_libfuzzer=true' },
 
     'lsan': {

tools/mb/mb_config_expectations/tryserver.chromium.chromiumos.json

@@ -128,6 +128,7 @@
   },
   "linux-lacros-rel": {
     "gn_args": {
+      "also_build_ash_chrome": true,
       "chromeos_is_browser_only": true,
       "dcheck_always_on": true,
       "is_component_build": false,

tools/mb/mb_config_expectations/tryserver.chromium.linux.json

@@ -409,6 +409,7 @@
   },
   "linux-lacros-fyi-rel": {
     "gn_args": {
+      "also_build_ash_chrome": true,
       "chromeos_is_browser_only": true,
       "dcheck_always_on": true,
       "is_component_build": false,