Fix interpreter with profiling

Authored by simonmar on Mar 5 2018, 2:12 PM.

Description

Fix interpreter with profiling

This was broken by D3746 and/or D3809, but unfortunately we didn't
notice because CI at the time wasn't building the profiling way.

Test Plan:

cd testsuite/test/profiling/should_run
make WAY=ghci-ext-prof

Reviewers: bgamari, michalt, hvr, erikd

Subscribers: rwbarton, thomie, carter

GHC Trac Issues: Trac #14705

Differential Revision: https://phabricator.haskell.org/D4437

(cherry picked from commit 488d63d6899d223ef87c26c218f0cf81ac670a90)