[TablesNG] clusterfuzz: uninitialized read

Forgot to initialize a pointer to null.

Bug: 1172819
Change-Id: I7fd8fe5e5eab1d1780faedb8f258069eed1635ce
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2683545
Commit-Queue: Aleks Totic <atotic@chromium.org>
Reviewed-by: Morten Stenshorne <mstensho@chromium.org>
Cr-Commit-Position: refs/heads/master@{#852151}
diff --git a/css/css-tables/crashtests/uninitialized_read_crash.html b/css/css-tables/crashtests/uninitialized_read_crash.html
new file mode 100644
index 0000000..5aa3b22
--- /dev/null
+++ b/css/css-tables/crashtests/uninitialized_read_crash.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<link rel="help" href="https://crbug.com/1172819">
+
+<table style="height:69080px;width:100px;background: blue;border-spacing:2px;">
+
+<thead style="height:400%">
+  <tr style="height:18px"></tr>
+</thead>
+<tbody>
+  <tr style="height: 2712px"></tr>
+</tbody>
+<tbody>
+  <tr style="height: 1694px"></tr>
+</tbody>
+<tbody>
+  <tr style="height: 6436px"></tr>
+</tbody>
+</table>