SEATTLE – On a list of things to fix, infield defense would fall near the bottom for the rebuilding Astros. Third baseman Matt Dominguez, shortstop Marwin Gonzalez and second baseman Jose Altuve have been well above average with the glove this season. Monday night was an exception, though, costing the Astros dearly in a 3-2 loss against the Mariners at Safeco Field. “Give Seattle credit tonight,” Astros manager Bo Porter said. “They capitalized on our mistakes.” With a wicked splitter and nasty movement on all his pitches, Mariners righthander Hisashi Iwakuma doesn’t need much help. He has dominated opponents for more than a month. The Astros needed to play clean [.]