Revert of Update SCT serialization format in Expect-CT reports (patchset #3 id:40001 of https://codereview.chromium.org/2959593002/ )

Reason for revert:
Heap-buffer-overflow on Chromium OS ASAN builders during ChromeExpectCTReporterTest.SendReport.

Please see comments on revert CL for more detail.

Original issue's description:
> Update SCT serialization and other format details in Expect-CT reports
>
> This adds a net::ct::EncodeSignedCertificateTimestamp function alongside the
> existing CT serialization functions, and uses it to properly encode SCTs in
> Expect-CT reports.
>
> The relevant spec change is
> https://github.com/httpwg/http-extensions/commit/20c5cfd5ef5b630e142b3251ecafc004ad8f2092,
> though it hasn't made it into a published draft yet. Before, we were including a
> JSON object containing a subset of information from the SCT based on the source of
> the SCT, but that was deemed unnecessary and now the spec just says to include a
> standard serialization of the SCT.
>
> The other report format changes made to bring the implementation in line with the
> spec are:
> - Shortening the 'origin' string values
> - Wrapping the report in a JSON dictionary with a single 'expect-ct-report' key
>
> BUG=679012
>
> Review-Url: https://codereview.chromium.org/2959593002
> Cr-Commit-Position: refs/heads/master@{#482905}
> Committed: https://chromium.googlesource.com/chromium/src/+/19bd384f656790e8e409086b5b97a53b3a6f5921

TBR=mattm@chromium.org,estark@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=679012

Review-Url: https://codereview.chromium.org/2960163002
Cr-Commit-Position: refs/heads/master@{#482924}
5 files changed