[test] Add unittests to fuchsia trybot

TBR=tmrts@chromium.org

No-Try: true
Bug: chromium:1021522
Change-Id: I54574e451487c497b478bc084e97f3ec450b2fa8
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1910105Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Tamer Tas <tmrts@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64999}

infra/testing/builders.pyl

@@ -47,6 +47,16 @@
     ],
   },
   ##############################################################################
+  # Fuchsia
+  'v8_fuchsia_rel_ng_triggered': {
+    'swarming_dimensions' : {
+      'os': 'Ubuntu-16.04',
+    },
+    'tests': [
+      {'name': 'unittests'},
+    ],
+  },
+  ##############################################################################
   # Linux32
   'v8_linux_dbg_ng_triggered': {
     'swarming_dimensions' : {

tools/mb/mb.py

@@ -726,7 +726,6 @@ class MetaBuildWrapper(object):
         return ret
 
     android = 'target_os="android"' in vals['gn_args']
-    fuchsia = 'target_os="fuchsia"' in vals['gn_args']
     for target in swarming_targets:
       if android:
         # Android targets may be either android_apk or executable. The former
@@ -736,11 +735,6 @@ class MetaBuildWrapper(object):
         runtime_deps_targets = [
             target + '.runtime_deps',
             'obj/%s.stamp.runtime_deps' % label.replace(':', '/')]
-      elif fuchsia:
-        # Only emit a runtime deps file for the group() target on Fuchsia.
-        label = isolate_map[target]['label']
-        runtime_deps_targets = [
-          'obj/%s.stamp.runtime_deps' % label.replace(':', '/')]
       elif (isolate_map[target]['type'] == 'script' or
             isolate_map[target].get('label_type') == 'group'):
         # For script targets, the build target is usually a group,