Quota database: remove extra sql::Statement::step() call

I believe this will lead to an error when step() has already returned
false, which could explain SQLITE_MISUSE values. Removing this might
sidestep that error, but we're still left wondering why the statement
is failing to return data.

(cherry picked from commit 17d19c5)

Bug: 1446886
Change-Id: I5e1f7300f208aa8f3551678ccdcaff7559182c50
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4569298
Reviewed-by: Austin Sullivan <asully@chromium.org>
Commit-Queue: Evan Stade <estade@chromium.org>
Cr-Original-Commit-Position: refs/heads/main@{#1151904}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4590710
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Auto-Submit: Evan Stade <estade@chromium.org>
Cr-Commit-Position: refs/branch-heads/5790@{#387}
Cr-Branched-From: 1d71a33-refs/heads/main@{#1148114}

storage/browser/quota/quota_database.cc

@@ -1238,10 +1238,9 @@ QuotaErrorOr<BucketInfo> QuotaDatabase::CreateBucketInternal(
                                         /*last_accessed=*/now,
                                         /*last_modified=*/now, statement);
   QuotaErrorOr<BucketInfo> result = BucketInfoFromSqlStatement(statement);
-  const bool done = !statement.Step();
-  DCHECK(done);
 
   if (result.has_value()) {
+    CHECK(!statement.Step());
     // Commit immediately so that we persist the bucket metadata to disk before
     // we inform other services / web apps (via the Buckets API) that we did so.
     // Once informed, that promise should persist across power failures.