Manually remove many instances of a comma quirk arising from the reformat.

This removes many of the lines consisting only of a comma after the Blink
reformat. About half remain, though, because they are the result of
trailing elements of an initializer or argument list being within preprocessor
guards (most commonly ENABLE(ASSERT)), and there does not seem to be a nice
way of formatting those in Chromium style.

BUG=563793

CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2

Review-Url: https://codereview.chromium.org/2387263004
Cr-Commit-Position: refs/heads/master@{#423166}
44 files changed