Fix isolate errors on Android bots because fastbuild wasn't passed in.

R=vadimsh@chromium.org

Review URL: https://codereview.chromium.org/583343002

Cr-Commit-Position: refs/heads/master@{#295767}

build/android/pylib/gtest/setup.py

@@ -115,6 +115,7 @@ def _GenerateDepsDirUsingIsolate(suite_name, isolate_file_path=None):
       '--config-variable', 'CONFIGURATION_NAME', constants.GetBuildType(),
       '--config-variable', 'chromeos', '0',
       '--config-variable', 'component', 'static_library',
+      '--config-variable', 'fastbuild', '0',
       '--config-variable', 'icu_use_data_file_flag', '1',
       # TODO(maruel): This may not be always true.
       '--config-variable', 'target_arch', 'arm',