UTF8 fix for twitter-reported issue

tests/shell/mod.rs

@@ -29,6 +29,21 @@ mod pipeline {
         })
     }
 
+    #[test]
+    fn doesnt_break_on_utf8_command() {
+        let actual = nu!(
+            cwd: std::path::PathBuf::from("."),
+            r#"
+                sh -c "echo ö"
+            "#
+        );
+
+        assert!(
+            actual.contains("ö"),
+            format!("'{}' should contain ö", actual)
+        );
+    }
+
     #[test]
     fn can_process_row_as_it_argument_to_an_external_command_given_the_it_data_is_one_string_line()
     {