Bug 1377188, part 1 - Change the UA 'box-sizing' style to 'content-box' for <hr>. r=dholbert

MozReview-Commit-ID: 4s5Cj5FhkDe

layout/style/res/html.css

@@ -633,7 +633,7 @@ hr {
   margin-inline-end: auto;
   color: gray;
   -moz-float-edge: margin-box;
-  box-sizing: border-box;
+  box-sizing: content-box;
 }
 
 hr[size="1"] {

testing/web-platform/meta/html/rendering/non-replaced-elements/the-hr-element-0/align.html.ini

@@ -1,3 +0,0 @@
-[align.html]
-  type: reftest
-  expected: FAIL

testing/web-platform/meta/html/rendering/non-replaced-elements/the-hr-element-0/hr.html.ini

@@ -3,9 +3,3 @@
   [overflow]
     expected: FAIL
 
-  [height]
-    expected: FAIL
-
-  [box-sizing]
-    expected: FAIL
-

testing/web-platform/meta/html/rendering/non-replaced-elements/the-hr-element-0/width.html.ini

@@ -1,3 +1,4 @@
 [width.html]
   type: reftest
-  expected: FAIL
+  expected:
+    if (os == "mac") or (os == "win"): FAIL