Summary: Ref T12297. This slightly modernizes the XHProf UI. Not included here: - Some of the code acts like samples have PHIDs, but they currently do not. I plan to add them in the next change. - I've intentionally left the actual list untouched for now -- it has some old/buggy code (like `flag-6` is no longer an icon) that I'll fix in a future change. Test Plan: {F3224264} Reviewers: chad Reviewed By: chad Maniphest Tasks: T12297 Differential Revision: https://secure.phabricator.com/D17400