Fix failing TranslationHelperTest

A simplification to TranslationHelper's translate method's handling of options caused a test failure:

1) Error: test_delegates_to_i18n_setting_the_raise_option(TranslationHelperTest): IndexError: index 3969 out of string

./test/../lib/action_view/helpers/translation_helper.rb:7:in `[]='
./test/../lib/action_view/helpers/translation_helper.rb:7:in `translate'
./test/template/translation_helper_test.rb:14:in `test_delegates_to_i18n_setting_the_raise_option'
./test/../../activesupport/lib/active_support/testing/setup_and_teardown.rb:94:in `__send__'
./test/../../activesupport/lib/active_support/testing/setup_and_teardown.rb:94:in `run'

The test was sending the locale String as the second argument to translate, which was treating it as its options Hash, leading to an error when it tried to index the locale string using a Symbol.