Remove an unused support check, correct a comment. Close gh-1211.

src/support.js

@@ -85,7 +85,6 @@ jQuery.support = (function( support ) {
 		jQuery.swap( body, body.style.zoom != null ? { zoom: 1 } : {}, function() {
 			support.boxSizing = div.offsetWidth === 4;
 		});
-		support.doesNotIncludeMarginInBodyOffset = body.offsetTop !== 1;
 
 		// Use window.getComputedStyle because jsdom on node.js will break without it.
 		if ( window.getComputedStyle ) {

src/traversing.js

@@ -250,7 +250,7 @@ jQuery.extend({
 // Implement the identical functionality for filter and not
 function winnow( elements, qualifier, keep ) {
 
-	// Can't pass null or undefined to indexOf in Firefox 4
+	// Can't pass null or undefined to indexOf
 	// Set to 0 to skip string check
 	qualifier = qualifier || 0;