Update [video-]dynamic-range media queries

As of the latest discussion on the spec, it's been determined that
'[video-]dynamic-range: standard' should be a subset of
'[video-]dynamic-range: high'. This CL implements that change, and
updates all tests accordingly. The relevant spec discussion may be
viewed here:
w3c/csswg-drafts#6793

Bug: 1224711
Change-Id: I640e574cd2809dc1d8b721115e79372d302c723a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3293745
Reviewed-by: Anders Hartvoll Ruud 
Commit-Queue: Will Cassella 
Cr-Commit-Position: refs/heads/main@{#944203}

Author: willcassella

css/mediaqueries/dynamic-range.html

@@ -35,15 +35,13 @@
 
 test(() => {
   let match_standard = window.matchMedia("(dynamic-range: standard)");
-  let match_high = window.matchMedia("(dynamic-range: high)");
-  assert_not_equals(match_standard.matches, match_high.matches);
-}, "Check that dynamic-range is 'standard' or 'high', but not both");
+  assert_true(match_standard.matches);
+}, "Check that dynamic-range always matches 'standard'");
 
 test(() => {
   let match_standard = window.matchMedia("(video-dynamic-range: standard)");
-  let match_high = window.matchMedia("(video-dynamic-range: high)");
-  assert_not_equals(match_standard.matches, match_high.matches);
-}, "Check that video-dynamic-range is 'standard' or 'high', but not both");
+  assert_true(match_standard.matches);
+}, "Check that video-dynamic-range always matches 'standard'");
 
 test(() => {
   let match_invalid = window.matchMedia("(video-dynamic-range: invalid)");