The original implementation of matching was a RegExp on the source
which wasn't able to reliably distinguish between comments inside
of string literals and actual comments. For that reason, it had
a special rule to disallow quotes to remove false positives.

Original comment:
> Also, ['"] are excluded from allowed URLs to  avoid matches
> against sources that invoke evals with sourceURL.

After the code was moved into the scanner, that shouldn't be an
issue anymore - the scanner knows that this is a real comment and
isn't part of a string literal.

Allowing quotes enables a slightly smaller encoding of source maps,
specifically in the case where there are no sourceContents:
Non-base64 source maps can get away with effectively no encoding
overhead (they typically don't contain whitespace).

Change-Id: Iffa5df28d80656fa56e603e7c0e57aa1f44d0014
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2576801Reviewed-by: Marja Hölttä <marja@chromium.org>
Auto-Submit: Jan Krems <jankrems@google.com>
Commit-Queue: Jan Krems <jankrems@google.com>
Cr-Commit-Position: refs/heads/master@{#71742}