[ObjC ARC] Converts ios/web/public/test/http_server:http_server to ARC.

Automatically generated ARCMigrate commit
Notable issues:None
BUG=624363
TEST=None

Review-Url: https://codereview.chromium.org/2923563005
Cr-Commit-Position: refs/heads/master@{#478161}
12 files changed