Disabled accessibility test of <br> element in preparation of a Blink change.

BUG=470124
R=dmazzoni

Review URL: https://codereview.chromium.org/1026353003

Cr-Commit-Position: refs/heads/master@{#322009}

content/browser/accessibility/dump_accessibility_tree_browsertest.cc

@@ -597,7 +597,7 @@ IN_PROC_BROWSER_TEST_F(DumpAccessibilityTreeTest, AccessibilityBody) {
   RunHtmlTest(FILE_PATH_LITERAL("body.html"));
 }
 
-IN_PROC_BROWSER_TEST_F(DumpAccessibilityTreeTest, AccessibilityBR) {
+IN_PROC_BROWSER_TEST_F(DumpAccessibilityTreeTest, DISABLED_AccessibilityBR) {
   RunHtmlTest(FILE_PATH_LITERAL("br.html"));
 }