layout: Add *very* basic support for table layout (#31121)

* layout: Add *very* basic support for table layout

This is the first step to proper table layout. It implements a naive
layout algorithm, notably only taking into account the preferred widths
of the first table row. Still, it causes some float tests to start
passing, so turn on the `layout.tables.enabled` preference for those
directories.

Co-authored-by: Oriol Brufau <obrufau@igalia.com>

* Address review comments

* Fix a crash with rowspan=0

* Turn on pref and update results for `/css/css-tables` and `/css/CSS2/tables`

---------

Co-authored-by: Oriol Brufau <obrufau@igalia.com>

tests/wpt/meta/css/css-tables/height-distribution/computing-row-measure-0.html.ini

@@ -4,3 +4,9 @@
 
   [Checking intermediate min-content height for span 1 (3)]
     expected: FAIL
+
+  [Checking intermediate min-content height for span 1 (2)]
+    expected: FAIL
+
+  [Checking intermediate min-content height for span 1 (4)]
+    expected: FAIL

tests/wpt/meta/css/css-tables/height-distribution/percentage-sizing-of-table-cell-children.html.ini

@@ -11,11 +11,5 @@
   [Unresolvable percentage widths are resolved as auto in first pass (replaced elements)]
     expected: FAIL
 
-  [Unresolvable percentage widths are resolved as auto in first pass (unscrollable overflow)]
-    expected: FAIL
-
-  [Unresolvable percentage widths are resolved as auto in first pass (scrollable overflow)]
-    expected: FAIL
-
   [Unresolvable percentage heights are resolved as 0px in first pass (scrollable overflow)]
     expected: FAIL

tests/wpt/meta/css/css-tables/height-distribution/td-different-subpixel-padding-in-same-row-vertical-rl.html.ini

@@ -0,0 +1,2 @@
+[td-different-subpixel-padding-in-same-row-vertical-rl.html]
+  expected: FAIL

tests/wpt/meta/css/css-tables/height-distribution/td-different-subpixel-padding-in-same-row.html.ini

@@ -1,2 +0,0 @@
-[td-different-subpixel-padding-in-same-row.html]
-  expected: FAIL