Fix presubmit error on third_party/WebKit/LayoutTests/OWNERS

SyntaxErrorInOwnersFile: /home/amoseui/Workspace/chromium/src/third_party/WebKit/LayoutTests/OWNERS:4
syntax error: //third_party/WebKit/Tools/OWNERS does not refer to an existing file.

third_party/WebKit/Tools/OWNERS was removed in https://crrev.com/c/1338583
Replace third_party/WebKit/Tools/OWERS with third_party/blink/tools/OWNERS
as it was included in third_party/WebKit/Tools/OWERS.

NOTRY=true
NOPRESUBMIT=true

Bug: 829697
Change-Id: I3ac65d16964b8dbbbaad9228d37dec88c0577f80
Reviewed-on: https://chromium-review.googlesource.com/c/1341440
Commit-Queue: Kent Tamura <tkent@chromium.org>
Reviewed-by: Kent Tamura <tkent@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609169}

third_party/WebKit/LayoutTests/OWNERS

 *
 
 per-file SmokeTests=set noparent
-per-file SmokeTests=file://third_party/WebKit/Tools/OWNERS
+per-file SmokeTests=file://third_party/blink/tools/OWNERS