Remove //third_party/WebKit/Tools/.gitattributes

This patch removes //third_party/WebKit/Tools/.gitattributes to make the
directory empty as follow-up of the patch[1].

[1] http://crrev.com/c/1338583 Remove //third_party/WebKit/Tools and //blink

No-Try: true
Bug: 829697
Change-Id: Icae6924a6365e9b32c274dbb063914c03f052279
Reviewed-on: https://chromium-review.googlesource.com/c/1350560
Commit-Queue: Kent Tamura <tkent@chromium.org>
Reviewed-by: Kent Tamura <tkent@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611012}

third_party/WebKit/Tools/.gitattributes

-TestResultServer/index.yaml -crlf