Bug 1015482 part 1: Add 'min-width: 0' to some reftest files that have flex items with intentionally-overflowing contents. r=mats

layout/reftests/w3c-css/submitted/flexbox/flexbox-collapsed-item-baseline-1-ref.html

@@ -23,6 +23,7 @@
     }
     .hiddenItemForSizing {
       width: 0;
+      min-width: 0; /* disable default min-width:auto behavior */
       color: transparent;
       align-self: baseline;
     }

layout/reftests/w3c-css/submitted/flexbox/flexbox-items-as-stacking-contexts-2.html

@@ -33,10 +33,12 @@
     .item1 {
       background: lightblue;
       width: 30px;
+      min-width: 0; /* disable default min-width:auto behavior */
     }
     .item2 {
       background: yellow;
       width: 30px;
+      min-width: 0; /* disable default min-width:auto behavior */
     }
   </style>
 </head>

layout/reftests/w3c-css/submitted/flexbox/flexbox-items-as-stacking-contexts-3.html

@@ -29,6 +29,7 @@
     .item1 {
       background: lightblue;
       width: 30px;
+      min-width: 0; /* disable default min-width:auto behavior */
       padding: 2px;
     }
     .item2 {