[wpt] Fix border-collapse-offset

This test failed the same way in all browsers:
https://wpt.fyi/results/css/CSS2/tables?label=experimental&label=master&aligned

With the fix, the test passes in all browsers.

offset1:

Collapsed
- cell border box height is 36 (2* half border + padding)
- cell content box height is 30

Non-collapsed
- cell border box height is 40
- cell content box is 30 (40 - 2*border - padding)

Similar problem with offset2. I believe original test did not
account for padding.

Bug: 958381
Change-Id: I1c851f24a33aa16152b2a7607804ecfed3d1f8d8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2587551
Commit-Queue: Aleks Totic <atotic@chromium.org>
Commit-Queue: David Grogan <dgrogan@chromium.org>
Auto-Submit: Aleks Totic <atotic@chromium.org>
Reviewed-by: David Grogan <dgrogan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#836266}

third_party/blink/web_tests/TestExpectations

@@ -2412,8 +2412,6 @@ crbug.com/1105958 external/wpt/payment-request/payment-is-showing.https.html [ T
 ### external/wpt/css/CSS2/tables/
 crbug.com/958381 external/wpt/css/CSS2/tables/border-collapse-dynamic-row-002.xht [ Failure ]
 crbug.com/958381 external/wpt/css/CSS2/tables/border-collapse-dynamic-rowgroup-002.xht [ Failure ]
-crbug.com/958381 external/wpt/css/CSS2/tables/border-collapse-offset-001.xht [ Failure ]
-crbug.com/958381 external/wpt/css/CSS2/tables/border-collapse-offset-002.xht [ Failure ]
 crbug.com/958381 external/wpt/css/CSS2/tables/caption-side-applies-to-007.xht [ Failure ]
 crbug.com/958381 external/wpt/css/CSS2/tables/column-visibility-004.xht [ Failure ]
 crbug.com/958381 external/wpt/css/CSS2/tables/fixed-table-layout-017.xht [ Failure ]

third_party/blink/web_tests/external/wpt/css/CSS2/tables/border-collapse-offset-001-ref.xht

@@ -10,9 +10,9 @@ div {position:absolute; border:green 4px solid}
 <!-- the height for table cells includes the border -->
 <div>
 <table cellspacing="0">
-  <tbody><tr><td style="border:solid 4px orange; height:34px">cell 1</td></tr>
+  <tbody><tr><td style="border:solid 4px orange; height:30px">cell 1</td></tr>
 </tbody></table>
 </div>
 
 
-</body></html>
\ No newline at end of file
+</body></html>

third_party/blink/web_tests/external/wpt/css/CSS2/tables/border-collapse-offset-002-ref.xht

@@ -11,9 +11,9 @@ caption {border:solid 4px green}
 
 <table cellpadding="0" cellspacing="0"><caption>caption</caption>
   <tbody><tr>
-    <td style="border:solid 4px orange; width:102px; height:34px">cell 1</td>
+    <td style="border:solid 4px orange; width:102px; height:32px">cell 1</td>
   </tr>
 </tbody></table>
 
 
-</body></html>
\ No newline at end of file
+</body></html>