Drop _oldapi from ACM test file names

Updating GN files, include paths, and include guards

BUG=None
NOTRY=True
NOPRESUBMIT=true

Review-Url: https://codereview.webrtc.org/2387113005
Cr-Commit-Position: refs/heads/master@{#14542}
diff --git a/webrtc/modules/audio_coding/BUILD.gn b/webrtc/modules/audio_coding/BUILD.gn
index 9b90959..d1dc1ed 100644
--- a/webrtc/modules/audio_coding/BUILD.gn
+++ b/webrtc/modules/audio_coding/BUILD.gn
@@ -891,8 +891,8 @@
   rtc_source_set("acm_receive_test") {
     testonly = true
     sources = [
-      "acm2/acm_receive_test_oldapi.cc",
-      "acm2/acm_receive_test_oldapi.h",
+      "acm2/acm_receive_test.cc",
+      "acm2/acm_receive_test.h",
     ]
 
     defines = audio_coding_defines
@@ -907,8 +907,8 @@
   rtc_source_set("acm_send_test") {
     testonly = true
     sources = [
-      "acm2/acm_send_test_oldapi.cc",
-      "acm2/acm_send_test_oldapi.h",
+      "acm2/acm_send_test.cc",
+      "acm2/acm_send_test.h",
     ]
 
     defines = audio_coding_defines