Fix process004 on Windows

tests/all.T

 test('process001', extra_clean(['process001.out']), compile_and_run, [''])
 test('process002', extra_clean(['process002.out']), compile_and_run, [''])
 test('process003', omit_ways(['ghci']), compile_and_run, [''])
-
-if config.os == "mingw32":
-      proc004_config = exit_code(1)
-else:
-      proc004_config = normal
-
-test('process004', [ proc004_config, normalise_exe ], compile_and_run, [''])
+test('process004', normalise_exe, compile_and_run, [''])
 test('T1780', normal, compile_and_run, [''])
 test('process005', normal, compile_and_run, [''])
 test('process006', normal, compile_and_run, [''])

tests/process004.stderr-mingw32

-process004.exe: true: runInteractiveProcess: invalid argument (Invalid argument)

tests/process004.stdout-mingw32

 Exc: true: runInteractiveProcess: invalid argument (Invalid argument)
 Exc: true: runProcess: invalid argument (Invalid argument)
-