Build debugged prof runtimes

Authored by osa1 on Sep 10 2018, 5:53 AM.

Description

Build debugged prof runtimes

For some reason these were disabled. I find these quite useful when
debugging profiling issues, so enable them again.

Reviewers: bgamari, simonmar

Reviewed By: simonmar

Subscribers: rwbarton, carter

Differential Revision: https://phabricator.haskell.org/D5140