[CSS Grid Layout] Rename gridAutoFlow[Row|Column] to gridAutoFlow[Row|Column]Sparse

LayoutTests/fast/css-grid-layout/resources/grid.css

 .grid {
     display: grid;
     background-color: grey;
 }
 
 .indefiniteSizeGrid {
     display: grid;
     background-color: grey;
     width: -webkit-min-content;
     height: auto;
@@ skipping 133 matching lines @@
     background-color: indigo;
     grid-column: span 2;
     grid-row: span 3;
 }
 
 /* Grid element flow. */
 .gridAutoFlowStack {
     grid-auto-flow: stack;
 }
 
-/* FIXME: Rename to gridAutoFlowColumnSparse to be more explicit about the algorithm mode by default. */
-.gridAutoFlowColumn {
+.gridAutoFlowColumnSparse {
     grid-auto-flow: column;
 }
 
 .gridAutoFlowColumnDense {
     grid-auto-flow: column dense;
 }
 
-/* FIXME: Rename to gridAutoFlowRowSparse to be more explicit about the algorithm mode by default. */
-.gridAutoFlowRow {
+.gridAutoFlowRowSparse {
     grid-auto-flow: row;
 }
 
 .gridAutoFlowRowDense {
     grid-auto-flow: row dense;
 }
 
 /* This rule makes sure the container is smaller than any grid items to avoid distributing any extra logical space to them. */
 .constrainedContainer {
     width: 10px;
@@ skipping 20 matching lines @@
     -webkit-writing-mode: vertical-lr;
 }
 
 .horizontalBT {
     -webkit-writing-mode: horizontal-bt;
 }
 
 .directionRTL {
     direction: rtl;
 }