Move gn _run target generation into test().

media/BUILD.gn

Index: media/BUILD.gn
diff --git a/media/BUILD.gn b/media/BUILD.gn
index e8c0a87a91aa1188914a0313d2c2c243cbe904a9..b4d05e5e9e5039a2b9d4c4b0b568591485091e69 100644
--- a/media/BUILD.gn
+++ b/media/BUILD.gn
@@ -610,15 +610,6 @@ if (is_ios) {
   }
 }
 
-# TODO(GYP): Delete this after we've converted everything to GN.
-# The _run targets exist only for compatibility w/ GYP.
-group("media_unittests_run") {
-  testonly = true
-  deps = [
-    ":media_unittests",
-  ]
-}
-
 test("media_unittests") {
   sources = [
     "capture/content/animated_content_sampler_unittest.cc",
@@ -839,15 +830,6 @@ test("media_perftests") {
   }
 }
 
-# TODO(GYP): Delete this after we've converted everything to GN.
-# The _run targets exist only for compatibility w/ GYP.
-group("audio_unittests_run") {
-  testonly = true
-  deps = [
-    ":audio_unittests",
-  ]
-}
-
 # For running the subset of media_unittests that might require audio hardware
 # separately on GPU bots. media_unittests includes these too.
 test("audio_unittests") {