Fix space leaks

Authored by simonmar on Jun 18 2018, 11:18 AM.

Description

Fix space leaks

Summary:
All these were detected by -fghci-leak-check when GHC was
compiled *without* optimisation (e.g. using the "quick" build flavour).

Unfortunately I don't know of a good way to keep this working. I'd like
to just disable the -fghci-leak-check flag when the compiler is built
without optimisation, but it doesn't look like we have an easy way to do
that. And even if we could, it would be fragile anyway,

Test Plan: cd testsuite/tests/ghci; make

Reviewers: bgamari, hvr, erikd, tdammers

Subscribers: tdammers, rwbarton, thomie, carter

GHC Trac Issues: Trac #15246

Differential Revision: https://phabricator.haskell.org/D4872