Implement JSON processing in asan_symbolize.py.
Implement JSON processing in asan_symbolize.py.

Enable asan_symbolize.py to parse JSON summary files generated by the test
launcher. The script will look for output snippets, pipe them through the
symbolizer and write them back to the JSON file.

BUG=372458
R=phajdan.jr@chromium.org,glider@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/850093002

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#311886}

hgl888/chromium-crosswalk,hgl888/chromium-crosswalk,Fireblend/chromium-crosswalk,hgl888/chromium-crosswalk,axinging/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,fujunwei/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,chuan9/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,Chilledheart/chromium,Pluto-tv/chromium-crosswalk,chuan9/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,Chilledheart/chromium,PeterWangIntel/chromium-crosswalk,Just-D/chromium-1,TheTypoMaster/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,Chilledheart/chromium,Fireblend/chromium-crosswalk,hgl888/chromium-crosswalk,Pluto-tv/chromium-crosswalk,hgl888/chromium-crosswalk,Fireblend/chromium-crosswalk,ltilve/chromium,fujunwei/chromium-crosswalk,Chilledheart/chromium,Pluto-tv/chromium-crosswalk,ltilve/chromium,Fireblend/chromium-crosswalk,ltilve/chromium,ltilve/chromium,PeterWangIntel/chromium-crosswalk,fujunwei/chromium-crosswalk,hgl888/chromium-crosswalk,chuan9/chromium-crosswalk,ltilve/chromium,PeterWangIntel/chromium-crosswalk,axinging/chromium-crosswalk,fujunwei/chromium-crosswalk,ltilve/chromium,TheTypoMaster/chromium-crosswalk,Chilledheart/chromium,chuan9/chromium-crosswalk,Just-D/chromium-1,PeterWangIntel/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,Pluto-tv/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Pluto-tv/chromium-crosswalk,hgl888/chromium-crosswalk,Fireblend/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,Chilledheart/chromium,Fireblend/chromium-crosswalk,chuan9/chromium-crosswalk,Just-D/chromium-1,TheTypoMaster/chromium-crosswalk,Chilledheart/chromium,Chilledheart/chromium,ltilve/chromium,fujunwei/chromium-crosswalk,axinging/chromium-crosswalk,Just-D/chromium-1,Fireblend/chromium-crosswalk,fujunwei/chromium-crosswalk,Pluto-tv/chromium-crosswalk,ltilve/chromium,TheTypoMaster/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,Chilledheart/chromium,Just-D/chromium-1,TheTypoMaster/chromium-crosswalk,ltilve/chromium,fujunwei/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,chuan9/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Just-D/chromium-1,Pluto-tv/chromium-crosswalk,fujunwei/chromium-crosswalk,hgl888/chromium-crosswalk,chuan9/chromium-crosswalk,chuan9/chromium-crosswalk,chuan9/chromium-crosswalk,Just-D/chromium-1,TheTypoMaster/chromium-crosswalk,axinging/chromium-crosswalk,Just-D/chromium-1,Fireblend/chromium-crosswalk,Fireblend/chromium-crosswalk,Just-D/chromium-1,axinging/chromium-crosswalk,fujunwei/chromium-crosswalk,hgl888/chromium-crosswalk