[3.0] Pass a list of rows to Db::insert(), not a single row

[albertlast]

Description

The fourth argument of Db::$db->insert() has to be an array of rows. Four call sites pass
one row's values directly. With $backward_compatibility on, the database layer quietly
wraps them; that is off by default in 3.0, and then insert() calls error_backtrace()
with E_USER_ERROR and the request dies with "Invalid data structure sent to the
database."

Logging::trackStats() is the bad one. The UPDATE it tries first matches nothing on
the first tracked event of a new day, so the insert runs, so the page is a 500 — and
because the row is never created, so is every page after it, for the rest of the day. It
takes hitStats being on, or a post, a new topic or a registration being the first thing
tracked that day.

Reproduced on a clean install with hitStats on:

DELETE FROM smf_log_activity WHERE date = CURDATE();
curl -o /dev/null -w '%{http_code}\n' http://localhost:8080/index.php   # 500
curl -o /dev/null -w '%{http_code}\n' http://localhost:8080/index.php   # 500
curl -o /dev/null -w '%{http_code}\n' http://localhost:8080/index.php   # 500, and so on

smf_log_errors fills with Invalid data structure sent to the database.<br>Function: trackStats at Sources/Logging.php:494. With this change the first request answers 200,
creates the row and increments hits from then on.

The other three are narrower:

• Display::checkMovedMergedRedirect() — marking a moved or merged topic read on the way
  through the redirect.
• User::logSpider() — the first page a spider fetches each day, when spider_mode is 1.
• Theme::loadVariant() — saving a member's chosen theme variant.

How this was checked

trackStats() end to end, as above. The other three by inspection: they are the same
misuse of the same argument, and each is unreachable on a stock install without a
configuration this environment does not have — the default theme ships
theme_variants = [], and a spider request dies earlier anyway, on
Typed property SMF\User::$timezone must not be accessed before initialization from
Sources/Time.php:191, which is a separate bug and unchanged either way.

No test: every one of these needs Db::$db, which the unit suite has no connection for.

NotifyTopic::changePref() has the same fault and is deliberately left alone here, because
#9477 already fixes it along with two other faults on that path.

Issues References (Fixes|Related|Closes)

1. Related: [3.0] Save the notification preference the member asked for #9477