Backfill OWNERS for VtsHalGraphicsMapper tests.

Done for the following tests:
VtsHalGraphicsMapperV2_0TargetTest
VtsHalGraphicsMapperV2_1TargetTest
VtsHalGraphicsMapperV3_0TargetTest
VtsHalGraphicsMapperV4_0TargetTest

Deleted the OWNERS file I created earlier to comply to your team's
convention.

Test: Tree Hugger
Bug: 143903671
Change-Id: I07790171fc1a42da37a43f590d8c5c2876ad1bfe
diff --git a/graphics/mapper/2.0/vts/OWNERS b/graphics/mapper/2.0/vts/OWNERS
index 4177296..62e3f2a 100644
--- a/graphics/mapper/2.0/vts/OWNERS
+++ b/graphics/mapper/2.0/vts/OWNERS
@@ -1,8 +1,5 @@
-# Graphics team
+# Bug component: 25423
 chrisforbes@google.com
 jreck@google.com
 lpy@google.com
-
-# VTS team
-yim@google.com
-zhuoyao@google.com
+sumir@google.com