Tests: Use closeEnough() to account for rounding differences

Selectmenu's test suite broke with b0e8380, which changed the padding
used by the menu widget. Selectmenu conditionally adds pixels to the
menu's width, and using closeEnough() accounts for that and the
rounding differences across browsers.

Closes jquerygh-1275

Author: tjvantoll

tests/unit/selectmenu/selectmenu_options.js

@@ -98,7 +98,7 @@ test( "Width", function() {
 
 	equal( button.outerWidth(), element.outerWidth(), "button width auto" );
 	element.selectmenu( "open" );
-	equal( menu.outerWidth(), element.outerWidth(), "menu width auto" );
+	closeEnough( menu.outerWidth(), element.outerWidth(), 2, "menu width auto" );
 
 	element.outerWidth( 100 );
 	element.selectmenu( "refresh" );