Also updated some tests due to the change. The general pattern is when a
trailing comma is expected to cause a SyntaxError, an additional comma was
added.
BUG=v8:5051
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel
Review-Url: https://codereview.chromium.org/2638513002
Cr-Commit-Position: refs/heads/master@{#42826}
This commit is a precursor to making lazy arrow function parsing use
similar logic to function(){} argument parsing.
R=arv@chromium.org
BUG=4020
LOG=N
Review URL: https://codereview.chromium.org/1078093002
Cr-Commit-Position: refs/heads/master@{#27773}