Android: Add OWNERS file to chrome/javatests/.../gesturenav

Adds myself as an owner of gesturenav/ in javatests

Bug: 937946
Change-Id: Ib1cdc2119855355ce8db55ff0e4ecc31bab72cf5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1850682Reviewed-by: Theresa  <twellington@chromium.org>
Commit-Queue: Jinsuk Kim <jinsukkim@chromium.org>
Cr-Commit-Position: refs/heads/master@{#704866}

chrome/android/javatests/src/org/chromium/chrome/browser/gesturenav/OWNERS

+file://chrome/android/java/src/org/chromium/chrome/browser/gesturenav/OWNERS
+
+# TEAM: chrome-android-app@chromium.org
+# COMPONENT: UI>Browser>Mobile
+# OS: Android