update-w3c-deps: Do not modify testharness tests.

third_party/WebKit/LayoutTests/imported/wpt/quirks-mode/supports.html

-<!-- quirks -->
+<!--quirks-->
 <title>Syntax quirks in @supports/CSS.supports</title>
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
 <link rel=help href=https://drafts.csswg.org/css-conditional/#at-supports>
 <link rel=help href=https://drafts.csswg.org/css-conditional/#the-css-interface>
 <link rel=help href=https://quirks.spec.whatwg.org/#the-hashless-hex-color-quirk>
 <link rel=help href=https://quirks.spec.whatwg.org/#the-unitless-length-quirk>
 <style>
  /* sanity check */
  @supports (background-color: lime) { #a { background-color: lime } }
  @supports (background-position: 1px 1px) { #a { background-position: 1px 1px } }
  /* test */
  @supports (background-color: 00ff00) { #b { background-color: 00ff00 } }
  @supports (background-position: 1 1) { #b { background-position: 1 1 } }
 </style>
 <div id=a></div>
 <div id=b></div>
-<div id=c></div> <!--  c unstyled  -->
+<div id=c></div> <!-- c unstyled -->
 <script>
 var a = document.getElementById('a');
 var b = document.getElementById('b');
 var c = document.getElementById('c');
 
 test(function() {
   assert_not_equals(getComputedStyle(a).backgroundColor, getComputedStyle(c).backgroundColor);
 }, 'Sanity check @supports color');
 
 test(function() {
   assert_equals(getComputedStyle(b).backgroundColor, getComputedStyle(a).backgroundColor);
 }, '@supports quirky color');
 
 test(function() {
   assert_false(CSS.supports('background-color', '00ff00'));
 }, 'CSS.supports() quirky color');
 
 test(function() {
   assert_not_equals(getComputedStyle(a).backgroundPosition, getComputedStyle(c).backgroundPosition);
 }, 'Sanity check @supports length');
 
 test(function() {
   assert_equals(getComputedStyle(b).backgroundPosition, getComputedStyle(a).backgroundPosition);
 }, '@supports quirky length');
 
 test(function() {
   assert_false(CSS.supports('background-position', '1 1'));
 }, 'CSS.supports() quirky length');
 </script>