Fix IPE test

A helper function was defined in a different module than used.
To reproduce: ./hadrian/build test --test-root-dirs=testsuite/tests/rts/ipe

testsuite/tests/rts/all.T

@@ -216,10 +216,6 @@ test('EventlogOutput_IPE',
      ],
      makefile_test, ['EventlogOutput_IPE'])
 
-# Remove the capability prefix from IPE event log lines.
-def noCapabilityOutputFilter(s):
-     return re.sub(r'[a-f0-9]+: IPE:', 'IPE:', s)
-
 test('T4059', req_c, makefile_test, ['T4059'])
 
 # Test for #4274

testsuite/tests/rts/ipe/all.T

+# Remove the capability prefix from IPE event log lines.
+def noCapabilityOutputFilter(s):
+     return re.sub(r'[a-f0-9]+: IPE:', 'IPE:', s)
+
 test('ipeMap', [extra_files(['ipe_lib.c', 'ipe_lib.h']), c_src, omit_ghci], compile_and_run, ['ipe_lib.c'])
 
 # Manually create IPE entries and dump them to event log (stderr).