Remove orphaned staticrange/OWNERS

Only test was removed in https://github.com/w3c/web-platform-tests/pull/9967.

No-Try: true
Change-Id: I9cb46906d621d25261476f5de414622f694d4173
Reviewed-on: https://chromium-review.googlesource.com/1039191Reviewed-by: Gary Kacmarcik <garykac@chromium.org>
Commit-Queue: Gary Kacmarcik <garykac@chromium.org>
Cr-Commit-Position: refs/heads/master@{#555412}

third_party/WebKit/LayoutTests/external/wpt/staticrange/OWNERS

-# TEAM: input-dev@chromium.org
-# COMPONENT: Blink>Input
-chongz@chromium.org
-garykac@chromium.org