Add a timeout for #8431

testsuite/tests/parser/should_fail/all.T

@@ -81,4 +81,4 @@ test('T984', normal, compile_fail, [''])
 test('T7848', normal, compile_fail, ['-dppr-user-length=100'])
 test('ExportCommaComma', normal, compile_fail, [''])
 test('T8430', literate, compile_fail, [''])
-test('T8431', normal, compile_fail, ['-XAlternativeLayoutRule'])
+test('T8431', [timeout_multiplier(0.05)], compile_fail, ['-XAlternativeLayoutRule'])