     <li>The <tt>--big-transactions</tt> flag is important for two
          of the bigger tests. Without it, those tests create many
          thousands of implicit transactions, reducing the affected
          tests to an absolute crawl, in particular with OPFS.
        </li>
        <li>The easiest way to try different optimization levels is,
          from this directory:
          <pre>$ rm -f jswasm/speedtest1.js; make -e emcc_opt='-O2' speedtest1</pre>
          Then reload this page. -O2 seems to co