Rename LargeDistributionWithLayout perf test to LargeDistributionWithoutLayout

This perf test never actually tested layout and making it test layout by
adding an offsetLeft call like the SmallDistributionWithLayout test is
a 100% perf regression and makes the test get less than 1 run per second
which isn't super useful. Instead we make the test a test of distribution
*without* layout since all the other distribution perf tests include layout
time.

Review URL: https://chromiumcodereview.appspot.com/22044002

git-svn-id: svn://svn.chromium.org/blink/trunk@156172 bbb929c8-8fbe-4397-9dbb-9b2b20218538