Refactor webrtc/{api,audio} and modules/audio_coding for GN check

.gn

Index: .gn
diff --git a/.gn b/.gn
index 7ed519fb3994097dd2cbef897dc0c315881e2f88..c44ccc8f6e7576eed08a73b2985f4818b01ee4fe 100644
--- a/.gn
+++ b/.gn
@@ -22,22 +22,9 @@ secondary_source = "//build/secondary/"
 # "gn check" or "gn gen --check".
 # TODO(kjellander): Keep adding paths to this list as work in webrtc:5589 is done.
 check_targets = [
-  "//webrtc/api:audio_mixer_api",
-  "//webrtc/api:transport_api",
-  "//webrtc/api:rtc_stats_api",
-  "//webrtc/audio/utility/*",
-  "//webrtc/modules/audio_coding:audio_decoder_factory_interface",
-  "//webrtc/modules/audio_coding:audio_format",
-  "//webrtc/modules/audio_coding:audio_format_conversion",
-  "//webrtc/modules/audio_coding:g711_test",
-  "//webrtc/modules/audio_coding:g722_test",
-  "//webrtc/modules/audio_coding:ilbc_test",
-  "//webrtc/modules/audio_coding:isac",
-  "//webrtc/modules/audio_coding:isac_api_test",
-  "//webrtc/modules/audio_coding:isac_fix_test",
-  "//webrtc/modules/audio_coding:isac_switch_samprate_test",
-  "//webrtc/modules/audio_coding:isac_test",
-  "//webrtc/modules/audio_coding:webrtc_opus_fec_test",
+  "//webrtc/api/*",
+  "//webrtc/audio/*",
+  "//webrtc/modules/audio_coding/*",
   "//webrtc/modules/audio_device/*",
   "//webrtc/modules/audio_mixer/*",
   "//webrtc/stats:rtc_stats",