MB: Remove a --target-devices-file flag for JUnit tests on android.

Not needed since it doesn't run in a device. It will enable us to run JUnit
tests on android on swarming too :) and more good stuff like flakiness dashboard

BUG=chromium:497757
R=kjellander@webrtc.org

Review-Url: https://codereview.webrtc.org/2531993003
Cr-Commit-Position: refs/heads/master@{#15268}

tools/mb/mb.py

@@ -1091,11 +1091,11 @@ class MetaBuildWrapper(object):
       test_cmdline = [
           self.PathJoin('bin', 'run_%s' % target),
           '--logcat-output-file', '${ISOLATED_OUTDIR}/logcats',
-          '--target-devices-file', '${SWARMING_BOT_FILE}',
-          '-v',
       ]
+      if test_type != 'junit_test':
+        test_cmdline += ['--target-devices-file', '${SWARMING_BOT_FILE}',]
       cmdline = (['./../../build/android/test_wrapper/logdog_wrapper.py']
-                 + logdog_command + test_cmdline)
+                 + logdog_command + test_cmdline + ['-v'])
     else:
       extra_files = ['../../testing/test_env.py']
 

tools/mb/mb_unittest.py

@@ -457,7 +457,6 @@ class UnitTest(unittest.TestCase):
         '--name', 'unified_logcats',
         'bin/run_base_unittests',
         '--logcat-output-file', '${ISOLATED_OUTDIR}/logcats',
-        '--target-devices-file', '${SWARMING_BOT_FILE}',
         '-v',
     ])