R1:7d496f2c6d7b

Collapse repository URI normalization code into Arcanist

Summary: Ref T13546. Companion change to D21372. Move URI normalization code to Arcanist to we can more-often resolve remote URIs correctly.

Test Plan: Grepped for affected symbols.

Maniphest Tasks: T13546

Differential Revision: https://secure.phabricator.com/D21373