Fix NPE in a unit test.

        for (final String word : words) {

            final UnigramProperty unigramProperty = binaryDictionary.getUnigramProperty(word);

            assertEquals((int)unigramProbabilities.get(word), unigramProperty.mProbability);

            if (!shortcutTargets.containsKey(word)) {

                // The word does not have shortcut targets.

                continue;

            }

            assertEquals(shortcutTargets.get(word).size(), unigramProperty.mShortcutTargets.size());

            for (final WeightedString shortcutTarget : unigramProperty.mShortcutTargets) {

                final String targetCodePonts = shortcutTarget.mWord;