Texas Roadhouse Shares Up on Market Debut  LOS ANGELES (Reuters) - Shares of restaurant operator Texas  Roadhouse Inc. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=TXRH.O target=/stocks/quickinfo/fullquote"&gt;TXRH.O&lt;/A&gt; soared as much as 28 percent in their  stock market debut on Tuesday after pricing above their  targeted range a day earlier.