Android: Add owners to help own CrashKeys

Now that CrashKeys.java and related files are in components/, tiborg@
and I can help isherman@ co-own these files to reduce maintenance
burden.

Bug: None
Change-Id: I790545b5976cdbd2109bfc57f8c615eacdbb6a90
Reviewed-on: https://chromium-review.googlesource.com/c/1355483
Commit-Queue: Ilya Sherman <isherman@chromium.org>
Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#612340}

components/crash/android/OWNERS

 isherman@chromium.org
+tiborg@chromium.org
+wnwen@chromium.org
 
 # COMPONENT: Internals>CrashReporting