Handle Unicode characters in adb log in Android tests

Bug: 1114450
Change-Id: Ie0518baca0bbc3f7835864dea236bcf2b676864e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2344663Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: Wei-Yin Chen (陳威尹) <wychen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#796275}

build/android/pylib/base/base_test_result.py

@@ -139,7 +139,7 @@ class TestRunResults(object):
             log = t.GetLog()
             if log:
               s.append('[%s] %s:' % (test_type, t))
-              s.append(log)
+              s.append(unicode(log, 'utf-8'))
       return '\n'.join(s)
 
   def GetGtestForm(self):