[GHC] #10164: Cleanup test framework string formatting

[GHC]

#10164: Cleanup test framework string formatting
-------------------------------------+-------------------------------------
        Reporter:  thomie            |                   Owner:
            Type:  task              |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Test Suite        |                 Version:  7.8.4
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  None/Unknown      |  Unknown/Multiple
      Blocked By:                    |               Test Case:
 Related Tickets:                    |                Blocking:
                                     |  Differential Revisions:
-------------------------------------+-------------------------------------

Comment (by thomie):

 In beee618c4ab8f725acd4dce3ef8a0d4ce84bb6ec/ghc:
 {{{
 commit beee618c4ab8f725acd4dce3ef8a0d4ce84bb6ec
 Author: Thomas Miedema <thomasmiedema at gmail.com>
 Date:   Sun Mar 15 21:06:39 2015 +0100

     Fix testsuite driver for a profiling compiler

     This should have been part of commit 5258566ee5c8, to allow expansion
 of
     '{hp2ps}' in a command string to `config.hp2ps`.

     Reviewed by: austin

     Differential Revision: https://phabricator.haskell.org/D734
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10164#comment:3>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler