Move gn _run target generation into test().

tools/battor_agent/BUILD.gn

Index: tools/battor_agent/BUILD.gn
diff --git a/tools/battor_agent/BUILD.gn b/tools/battor_agent/BUILD.gn
index 12fb7d5dbb0607a6b9ea31bc68997171e6b760b1..1a057f3f2b0336b1c5ae5e984c912600c6846f6c 100644
--- a/tools/battor_agent/BUILD.gn
+++ b/tools/battor_agent/BUILD.gn
@@ -59,12 +59,3 @@ test("battor_agent_unittests") {
     "//testing/gtest",
   ]
 }
-
-# TODO(GYP): Delete this after we've converted everything to GN.
-# The _run targets exist only for compatibility w/ GYP.
-group("battor_agent_unittests_run") {
-  testonly = true
-  deps = [
-    ":battor_agent_unittests",
-  ]
-}