Revert of Enabling `gn check` on webrtc/test

webrtc/modules/rtp_rtcp/BUILD.gn

Index: webrtc/modules/rtp_rtcp/BUILD.gn
diff --git a/webrtc/modules/rtp_rtcp/BUILD.gn b/webrtc/modules/rtp_rtcp/BUILD.gn
index a9e257ef6aa2c0ffabde264134266059ddbb2017..7f2d64fe5342aa62743d34a355a831e275073e3b 100644
--- a/webrtc/modules/rtp_rtcp/BUILD.gn
+++ b/webrtc/modules/rtp_rtcp/BUILD.gn
@@ -211,21 +211,6 @@
   }
 }
 
-rtc_source_set("mock_rtp_rtcp") {
-  testonly = true
-  sources = [
-    "mocks/mock_recovered_packet_receiver.h",
-    "mocks/mock_rtcp_rtt_stats.h",
-    "mocks/mock_rtp_rtcp.h",
-  ]
-  deps = [
-    ":rtp_rtcp",
-    "..:module_api",
-    "../../base:rtc_base_approved",
-    "../../test:test_support",
-  ]
-}
-
 if (rtc_include_tests) {
   rtc_executable("test_packet_masks_metrics") {
     testonly = true
@@ -263,6 +248,21 @@
       # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
       suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
     }
+  }
+
+  rtc_source_set("mock_rtp_rtcp") {
+    testonly = true
+    sources = [
+      "mocks/mock_recovered_packet_receiver.h",
+      "mocks/mock_rtcp_rtt_stats.h",
+      "mocks/mock_rtp_rtcp.h",
+    ]
+    deps = [
+      ":rtp_rtcp",
+      "..:module_api",
+      "../../base:rtc_base_approved",
+      "../../test:test_support",
+    ]
   }
 
   rtc_source_set("rtp_rtcp_unittests") {