Auto merge of #6977 - pcwalton:containing-block-link-crash, r=mbrubeck

layout: Make sure anonymous table flows are statically positioned.

The failing `float-applies-to-*` CSS 2.1 tests never really should have
been passing in the first place; they depend on floats inside
fixed-layout tables working properly, which they don't.

Closes #6078.
Closes #6709.
Closes #6858.

r? @mbrubeck

<!-- Reviewable:start -->
[<img src="https://reviewable.io/review_button.png" height=40 alt="Review on Reviewable"/>](https://reviewable.io/reviews/servo/servo/6977)
<!-- Reviewable:end -->

tests/wpt/metadata-css/css21_dev/html4/abspos-containing-block-initial-004c.htm.ini

@@ -1,3 +1,3 @@
 [abspos-containing-block-initial-004c.htm]
   type: reftest
-  expected: TIMEOUT
+  expected: FAIL

tests/wpt/metadata-css/css21_dev/html4/abspos-containing-block-initial-004d.htm.ini

@@ -1,3 +1,3 @@
 [abspos-containing-block-initial-004d.htm]
   type: reftest
-  expected: TIMEOUT
+  expected: FAIL

tests/wpt/metadata-css/css21_dev/html4/abspos-containing-block-initial-005b.htm.ini

@@ -1,3 +1,3 @@
 [abspos-containing-block-initial-005b.htm]
   type: reftest
-  expected: TIMEOUT
+  expected: FAIL

tests/wpt/metadata-css/css21_dev/html4/abspos-containing-block-initial-005d.htm.ini

@@ -1,3 +1,3 @@
 [abspos-containing-block-initial-005d.htm]
   type: reftest
-  expected: TIMEOUT
+  expected: FAIL

tests/wpt/metadata-css/css21_dev/html4/float-applies-to-001a.htm.ini

@@ -0,0 +1,4 @@
+[float-applies-to-001a.htm]
+  type: reftest
+  expected: FAIL
+

tests/wpt/metadata-css/css21_dev/html4/float-applies-to-004a.htm.ini

@@ -0,0 +1,4 @@
+[float-applies-to-004a.htm]
+  type: reftest
+  expected: FAIL
+

tests/wpt/metadata-css/css21_dev/html4/float-applies-to-005.htm.ini

@@ -0,0 +1,4 @@
+[float-applies-to-005.htm]
+  type: reftest
+  expected: FAIL
+

tests/wpt/metadata-css/css21_dev/html4/float-applies-to-006.htm.ini

@@ -0,0 +1,4 @@
+[float-applies-to-006.htm]
+  type: reftest
+  expected: FAIL
+