Repro test non-ASCII text format parsing

Cherry-pick from #730

Author: stepancheg

test-crates/protobuf-codegen-protoc-test/src/common/v2/test_fmt_text_format.rs

@@ -114,6 +114,13 @@ fn test_string_bytes() {
     );
 }
 
+#[test]
+fn non_ascii_strings() {
+    test_text_format_str_descriptor("string_singular: \"À\"", &TestTypes::descriptor());
+    // TODO: fix this.
+    // test_text_format_str_descriptor("string_singular: \"日月\"", &TestTypes::descriptor());
+}
+
 #[test]
 fn test_message() {
     test_text_format_str_descriptor("test_message_singular {}", &TestTypes::descriptor());