[css-flex] Add missing height attributes to some svg img flex items

Without a specified height, the rects should have received a 0 height.
It appears these tests passed in Chrome because of a Blink SVG bug that
gave the rects a height. These tests didn't pass in Firefox. See
https://bugzilla.mozilla.org/show_bug.cgi?id=1666643

Change-Id: I13053947e343572426f4e584d68bc52191482f02
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2425723
Auto-Submit: David Grogan <dgrogan@chromium.org>
Commit-Queue: Christian Biesinger <cbiesinger@chromium.org>
Reviewed-by: Christian Biesinger <cbiesinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#809747}

third_party/blink/web_tests/external/wpt/css/css-flexbox/flex-aspect-ratio-img-row-008.html

@@ -8,5 +8,5 @@
 <p>Test passes if there is a filled green square.</p>
 
 <div style="display: flex; width: 100px;">
-  <img src="data:image/svg+xml,%3Csvg viewBox='0 0 200 400' width='50px' xmlns='http://www.w3.org/2000/svg' %3E%3Crect width='100%' fill='green' /%3E%3C/svg%3E" style="border-left: 50px solid green; min-width: 0px;">
+  <img src="data:image/svg+xml,%3Csvg viewBox='0 0 200 400' width='50px' xmlns='http://www.w3.org/2000/svg' %3E%3Crect width='100%' height='100%' fill='green' /%3E%3C/svg%3E" style="border-left: 50px solid green; min-width: 0px;">
 </div>

third_party/blink/web_tests/external/wpt/css/css-flexbox/flex-aspect-ratio-img-row-009.html

@@ -22,5 +22,5 @@
 <div id=reference-overlapped-red></div>
 
 <div style="display: flex; width: 50px;">
-  <img src="data:image/svg+xml,%3Csvg viewBox='0 0 200 400' width='50px' xmlns='http://www.w3.org/2000/svg' %3E%3Crect width='100%' fill='green' /%3E%3C/svg%3E" style="border-left: 50px solid green;">
+  <img src="data:image/svg+xml,%3Csvg viewBox='0 0 200 400' width='50px' xmlns='http://www.w3.org/2000/svg' %3E%3Crect width='100%' height='100%' fill='green' /%3E%3C/svg%3E" style="border-left: 50px solid green;">
 </div>