feat: update tmx writer, escaper, and unit test

[miurahr]

Pull request type

• Feature enhancement -> [enhancement]

Which ticket is resolved?

• TMX writer output as same escape as OmegaT 6.0
  • https://sourceforge.net/p/omegat/feature-requests/1749/

What does this PR change?

• update TMX test expectation for level2 write
  • use double quote for attribute
  • format indentation and empty line
• Add TmxEscapingWriterFactory class and unit test with ordinary string, "< & >", Surrogate Pair and invalid one.
• Use TmxEscapingWriterFactory in TMXWriter2 for TEXT writer

Other information

com.sun.xml.bind.marshaller#escape which is ultimately OmegaT 6.0 and before use is as follows;

public void escape(char[] ch, int start, int length, boolean isAttVal, Writer out) throws IOException {
        int limit = start + length;

        for(int i = start; i < limit; ++i) {
            char c = ch[i];
            if (c == '&' || c == '<' || c == '>' || c == '\r' || c == '\n' && isAttVal || c == '"' && isAttVal) {
                if (i != start) {
                    out.write(ch, start, i - start);
                }

                start = i + 1;
                switch (ch[i]) {
                    case '\n':
                    case '\r':
                        out.write("&#");
                        out.write(Integer.toString(c));
                        out.write(59);
                        break;
                    case '"':
                        out.write("&quot;");
                        break;
                    case '&':
                        out.write("&amp;");
                        break;
                    case '<':
                        out.write("&lt;");
                        break;
                    case '>':
                        out.write("&gt;");
                        break;
                    default:
                        throw new IllegalArgumentException("Cannot escape: '" + c + "'");
                }
            }
        }

        if (start != limit) {
            out.write(ch, start, limit - start);
        }

    }