Replace 'outer_size' with 'size' attribute in test_data/memory_dumps.json
Replace 'outer_size' with 'size' attribute in test_data/memory_dumps.json

This is a follow-up for the recent change which removed support for
'outer_size' attribute in memory allocator dumps:
https://codereview.appspot.com/240700043

BUG=#849
TBR=primiano@chromium.org

Review URL: https://codereview.appspot.com/244450043.

dstockwell/catapult,SummerLW/Perf-Insight-Report,sahiljain/catapult,catapult-project/catapult-csm,benschmaus/catapult,catapult-project/catapult-csm,zeptonaut/catapult,dstockwell/catapult,catapult-project/catapult-csm,benschmaus/catapult,sahiljain/catapult,modulexcite/catapult,modulexcite/catapult,catapult-project/catapult,dstockwell/catapult,SummerLW/Perf-Insight-Report,catapult-project/catapult-csm,danbeam/catapult,benschmaus/catapult,benschmaus/catapult,catapult-project/catapult-csm,benschmaus/catapult,catapult-project/catapult,catapult-project/catapult-csm,catapult-project/catapult-csm,zeptonaut/catapult,0x90sled/catapult,sahiljain/catapult,SummerLW/Perf-Insight-Report,danbeam/catapult,sahiljain/catapult,benschmaus/catapult,catapult-project/catapult,scottmcmaster/catapult,scottmcmaster/catapult,SummerLW/Perf-Insight-Report,sahiljain/catapult,catapult-project/catapult,scottmcmaster/catapult,modulexcite/catapult,0x90sled/catapult,0x90sled/catapult,sahiljain/catapult,SummerLW/Perf-Insight-Report,catapult-project/catapult,dstockwell/catapult,catapult-project/catapult,danbeam/catapult,catapult-project/catapult,SummerLW/Perf-Insight-Report,danbeam/catapult,benschmaus/catapult,zeptonaut/catapult