t4151: consolidate multiple calls to test_i18ngrep

Attempting to grep the output of test_i18ngrep will not work under a poison build, since the output is (almost) guaranteed not to have the string you are looking for. In this case, we have a test_i18ngrep call which attempts to filter the contents of a file, which was itself the result of a call to test_i18ngrep. In this case, we can achieve the same effect with a single call to test_i18ngrep (without creating the intermediate file), since the second regular expression can be used without change to filter the original input. Also, replace a call to test_i18ncmp with test_cmp, since the content being compared is not subject to i18n anyway. Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>