(Reland: NeedsManualRebaseline'd newly-fixed layout test in Chromium.)

This was never legal; the spec only allows '\0' in strict-mode strings
or templates when not followed by a decimal digit. Previously we were
only enforcing that it not be followed by an _octal_ digit.

This was already fixed for numeric literals, but not for escape
sequences in strings.

BUG=v8:6504

Review-Url: https://codereview.chromium.org/2948903002
Cr-Commit-Position: refs/heads/master@{#46106}