[telemetry] find_dependencies: Skip abstract test classes when searching for page set data.
[telemetry] find_dependencies: Skip abstract test classes when searching for page set data.


BUG=None.
TEST=tools/telemetry_tools/find_dependencies content/test/gpu/run_gpu_test --include-page-set-data  # Doesn't crash.

Review URL: https://codereview.chromium.org/174543002

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@252463 0039d316-1c4b-4281-b951-d872f2087c98

SummerLW/Perf-Insight-Report,catapult-project/catapult-csm,sahiljain/catapult,catapult-project/catapult-csm,benschmaus/catapult,SummerLW/Perf-Insight-Report,catapult-project/catapult,catapult-project/catapult-csm,catapult-project/catapult-csm,benschmaus/catapult,sahiljain/catapult,catapult-project/catapult,catapult-project/catapult,benschmaus/catapult,benschmaus/catapult,SummerLW/Perf-Insight-Report,sahiljain/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,SummerLW/Perf-Insight-Report,catapult-project/catapult-csm,catapult-project/catapult-csm,benschmaus/catapult,benschmaus/catapult,SummerLW/Perf-Insight-Report,catapult-project/catapult-csm,sahiljain/catapult,sahiljain/catapult,catapult-project/catapult,benschmaus/catapult,sahiljain/catapult,SummerLW/Perf-Insight-Report