tests: clean up whitespace

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

Library/Homebrew/test/test_mach.rb

@@ -136,12 +136,6 @@ class MachOPathnameTests < Test::Unit::TestCase
 end
 
 class TextExecutableTests < Test::Unit::TestCase
-  TMPDIR = HOMEBREW_PREFIX/'tmp'
-
-  def setup
-    FileUtils.mkdir_p TMPDIR
-  end
-
   def test_simple_shebang
     pn = Pathname.new('foo')
     pn.write '#!/bin/sh'
@@ -189,8 +183,4 @@ class TextExecutableTests < Test::Unit::TestCase
     assert pn.arch == :dunno
     assert_no_match /text executable/, file(pn)
   end
-
-  def teardown
-    TMPDIR.rmtree
-  end
 end