Don't use Ahem font in LayoutTests/editing/selection/move-by-line-006.html

Don't use Ahem font in LayoutTests/editing/selection/move-by-line-006.html

This patch changes "move-by-line-006.html" to use "monospace" font instead of
"Ahem" font to mitigate flakiness on local Windows desktop.

When I run "move-by-line-006.html" on local Windows desktop, it is flaky, e.g.
failed on parallel test execution but succeeded on single execution.

BUG=n/a
TEST=n/a; no behavior changes

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=201856

[yosin_UTC9, 2015-09-07 02:05:39]

yosin@chromium.org changed reviewers:
+ yoichio@chromium.org

[yosin_UTC9, 2015-09-07 03:23:47]

yosin@chromium.org changed reviewers:
+ hajimehoshi@chromium.org

[yosin_UTC9, 2015-09-07 03:23:47]

PTAL

[hajimehoshi, 2015-09-07 04:54:33]

lgtm

[yosin_UTC9, 2015-09-07 04:55:03]

The CQ bit was checked by yosin@chromium.org

[commit-bot: I haz the power, 2015-09-07 04:55:07]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1314643006/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1314643006/1

[yoichio, 2015-09-07 04:57:44]

Why expect is changed?

[commit-bot: I haz the power, 2015-09-07 04:59:31]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=201856

[hajimehoshi, 2015-09-07 05:01:12]

On 2015/09/07 04:57:44, yoichio wrote:
> Why expect is changed?

I guess that's because the font was changed and the rendered text in a line was
changed.