Order inline comments in Diffusion consistently with Differential

Summary:
Fixes T8739. Currently, Diffusion inline comments in the timeline are sorted arbitrarily, mostly by creation order.

Instead, sort them by line number, like Differential.

Test Plan:
Made comments in "C", "B", "A" order, saw them in line order after submit:

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T8739

Differential Revision: https://secure.phabricator.com/D17184