Update DumpAccessibilityTreeTest to avoid crbug.com/961898

"inlineTextBox" in AX tree is a representation of text after
layout (line breaking,) and therefore every "staticText" and
"lineBreak" should have corresponding "inlineTextBox"es.

Sometimes "inlineTextBox" for "lineBreak" in AX tree is
missing when the `<br>` is after newline and spaces. This is
due to crbug.com/961898 where legacy fails to create
`InlineTextBox` for such `<br>`.

In order to make the switch to LayoutNG easier, this patch
changes the tests and expected files to avoid hitting the
condition, so that these tests produce the same results for
legacy and NG.

Change-Id: I53048fb53a1e9a78473b65556eea18eabc70fccc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1607000
Commit-Queue: Koji Ishii <kojii@chromium.org>
Reviewed-by: Christian Biesinger <cbiesinger@chromium.org>
Reviewed-by: Emil A Eklund <eae@chromium.org>
Reviewed-by: Alice Boxhall <aboxhall@chromium.org>
Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#658957}
4 files changed