Enable the CSS image-orientation always

The spec has been updated to something we can commit to.
Intent to Ship has been approved.

So implement the CSS image-orientation property for all
images (content and style) and change the valid values
to "from-image" or "none". Update tests accordingly.

This does not remove the flag in case we need to turn it
off.

Intent to Ship:
https://groups.google.com/a/chromium.org/forum/#!searchin/blink-dev/image-orientation%7Csort:date/blink-dev/jPgnRoivOis/X1E6SuOoAwAJ

Bug: 158753
Change-Id: Ib50d263b01f7cf6b2d17174138fd223a8105da8e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1846319
Reviewed-by: Chris Harrelson <[email protected]>
Commit-Queue: Stephen Chenney <[email protected]>
Cr-Commit-Position: refs/heads/master@{#725393}

css/css-images/inheritance.html

@@ -15,7 +15,7 @@
 <div id="target"></div>
 </div>
 <script>
-assert_inherited('image-orientation', '0deg', 'from-image'); // none is 0deg
+assert_inherited('image-orientation', 'from-image', 'none');
 assert_inherited('image-rendering', 'auto', 'pixelated');
 assert_not_inherited('object-fit', 'fill', 'contain');
 assert_not_inherited('object-position', '50% 50%', '10px 20px');