Add some more clean_cmd's

testsuite/tests/ghc-regress/module/mod175/all.T

 setTestOpts(only_compiler_types(['ghc']))
 
-test('mod175', expect_broken(437), run_command, ['$MAKE -s mod175'])
+test('mod175',
+     [expect_broken(437),
+      clean_cmd('$MAKE -s clean')],
+     run_command,
+     ['$MAKE -s mod175'])
 
 if default_testopts.cleanup != '':
     runCmd('$MAKE -C ' + in_testdir('') + ' clean')

testsuite/tests/ghc-regress/th/TH_recompile/all.T

@@ -7,8 +7,9 @@ setTestOpts(f)
 setTestOpts(only_compiler_types(['ghc']))
 setTestOpts(only_ways(['normal']));
 
-test('TH_recompile', expect_broken(481), run_command, ['$MAKE -s TH_recompile'])
-
-if default_testopts.cleanup != '':
-    runCmd('$MAKE -C ' + in_testdir('') + ' clean')
+test('TH_recompile',
+     [expect_broken(481),
+      clean_cmd('$MAKE -s clean')],
+     run_command,
+     ['$MAKE -s TH_recompile'])