Fixed small error in how ChromeSyncShellTest was run.

BUG=406538

Review URL: https://codereview.chromium.org/612933002

Cr-Commit-Position: refs/heads/master@{#300727}

build/android/buildbot/bb_device_steps.py

@@ -186,7 +186,7 @@ def RunChromeSyncShellTests(options):
   test = I('ChromeSyncShell',
            'ChromeSyncShell.apk',
            'org.chromium.chrome.browser.sync',
-           'ChromeSyncShellTest.apk',
+           'ChromeSyncShellTest',
            'chrome:chrome/test/data/android/device_files')
   RunInstrumentationSuite(options, test)