layout: Paint collapsed table borders on their own (#35075)

We were previously splitting collapsed borders into two halves, and then
paint each one as part of the corresponding cell. This looked wrong when
the border style wasn't solid, or when a cell spanned multiple tracks
and the border wasn't the same for all of them.

Now the borders of a table wrapper, table grid or table cell aren't
painted in collapsed borders mode. Instead, the resulting collapsed
borders are painted on their own.

Signed-off-by: Oriol Brufau <obrufau@igalia.com>

tests/wpt/meta/css/CSS2/normal-flow/block-formatting-contexts-003.xht.ini

@@ -1,2 +0,0 @@
-[block-formatting-contexts-003.xht]
-  expected: FAIL

tests/wpt/meta/css/CSS2/tables/border-conflict-element-001d.xht.ini

@@ -1,2 +0,0 @@
-[border-conflict-element-001d.xht]
-  expected: FAIL

tests/wpt/meta/css/CSS2/tables/collapsing-border-model-001.xht.ini

@@ -1,2 +0,0 @@
-[collapsing-border-model-001.xht]
-  expected: FAIL

tests/wpt/meta/css/CSS2/tables/collapsing-border-model-004.xht.ini

@@ -1,2 +0,0 @@
-[collapsing-border-model-004.xht]
-  expected: FAIL

tests/wpt/meta/css/css-backgrounds/box-shadow-table-border-collapse-001.html.ini

@@ -1,2 +0,0 @@
-[box-shadow-table-border-collapse-001.html]
-  expected: FAIL

tests/wpt/meta/css/css-backgrounds/ttwf-reftest-borderRadius.html.ini

@@ -1,2 +0,0 @@
-[ttwf-reftest-borderRadius.html]
-  expected: FAIL

tests/wpt/meta/css/css-tables/border-collapse-double-border.html.ini

@@ -1,2 +0,0 @@
-[border-collapse-double-border.html]
-  expected: FAIL

tests/wpt/meta/css/css-tables/collapsed-border-paint-phase-002.html.ini

@@ -1,2 +0,0 @@
-[collapsed-border-paint-phase-002.html]
-  expected: FAIL

tests/wpt/meta/css/css-tables/collapsed-border-positioned-tr-td.html.ini

@@ -0,0 +1,2 @@
+[collapsed-border-positioned-tr-td.html]
+  expected: FAIL

tests/wpt/mozilla/meta/gfx-rs-gecko/356774-1.html.ini

@@ -1,2 +0,0 @@
-[356774-1.html]
-  expected: FAIL