When the scanner finds a '-->', it's either part of an HTMLCloseComment
or a '--' followed by a '>'. Previously, only a preceding newline would
make it an HTMLCloseComment. Now, a preceding multiline comment also
makes it an HTMLCloseComment. The effect is that now the following is
not a SyntaxError:

x/*
*/-->this is now a comment

BUG=v8:5142
LOG=y

Review-Url: https://codereview.chromium.org/2119763003
Cr-Commit-Position: refs/heads/master@{#37656}