Remove 'has tabs' req from startup.*.blank_page tests.
Remove 'has tabs' req from startup.*.blank_page tests.

The "has tabs" requirement isn't needed and it blocks Mandoline.
The BlankPage* page sets only contain a single blank html page.
(these pass w/o times on browser=content-shell-debug, probably ok)
That req was added without apparent explicit necessity by these CLs:
  https://codereview.chromium.org/399053004
  https://codereview.chromium.org/335923007
  https://codereview.chromium.org/1056623002

Support mandoline.* browser-type prefix matching like content-shell.
Remove unnecessary 'win', 'linux', 'mac' enabled decorator.
Note the bug for 'reference' browser not supporting large profiles.

BUG=513779
TEST=startup.*.blank_page are available for --browser=mandoline-[debug|release].
CQ_EXTRA_TRYBOTS=tryserver.chromium.perf:linux_perf_bisect;tryserver.chromium.perf:mac_perf_bisect;tryserver.chromium.perf:android_nexus5_perf_bisect
R=yzshen@chromium.org,dtu@chromium.org
TBR=aiolos@chromium.org

Review URL: https://codereview.chromium.org/1303353006

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#346717}

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