R1:417ca39703c8

Update Phabricator to new PhutilServiceProfiler APIs

Summary:
Get rid of the Phabricator-level DarkConsole-specific API and use the more
general Phutil-level one.

Test Plan:
Loaded DarkConsole services plugin, viewed Diffusion, got execs in the trace.

Reviewed By: aran
Reviewers: aran, jungejason, tuomaspelkonen
CC: aran
Differential Revision: 293