Revert of Move gn _run target generation into test().

google_apis/BUILD.gn

Index: google_apis/BUILD.gn
diff --git a/google_apis/BUILD.gn b/google_apis/BUILD.gn
index d491b48544e0ce77bd2bf4caef1a593400e09b90..46048ffa5510f8a6f35f04d2312729bc1ff3285b 100644
--- a/google_apis/BUILD.gn
+++ b/google_apis/BUILD.gn
@@ -224,6 +224,15 @@
   }
 }
 
+# TODO(GYP): Delete this after we've converted everything to GN.
+# The _run targets exist only for compatibility w/ GYP.
+group("google_apis_unittests_run") {
+  testonly = true
+  deps = [
+    ":google_apis_unittests",
+  ]
+}
+
 test("google_apis_unittests") {
   sources = [
     "gaia/gaia_auth_fetcher_unittest.cc",