Revert "Reland "Split peer_connection_integrationtest.cc into pieces""

This reverts commit 772066b.

Reason for revert: Did not catch all missing INSTANTIATE_TEST_SUITE_P

Original change's description:
> Reland "Split peer_connection_integrationtest.cc into pieces"
>
> This reverts commit 8644f2b.
>
> Reason for revert: Fixed the bugs
>
> Original change's description:
> > Revert "Split peer_connection_integrationtest.cc into pieces"
> >
> > This reverts commit cae4656.
> >
> > Reason for revert: Breaks downstream build (missing INSTANTIATE_TEST_SUITE_P in pc/data_channel_integrationtest.cc).
> >
> > Original change's description:
> > > Split peer_connection_integrationtest.cc into pieces
> > >
> > > This creates two integration tests: One for datachannel, the other
> > > for every test that is not datachannel.
> > >
> > > It separates out the common framework to a new file in pc/test.
> > > Also applies some fixes to IWYU.
> > >
> > > Bug: None
> > > Change-Id: I919def1c360ffce205c20bec2d864aad9b179c3a
> > > Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/207060
> > > Reviewed-by: Henrik Boström <[email protected]>
> > > Commit-Queue: Harald Alvestrand <[email protected]>
> > > Cr-Commit-Position: refs/heads/master@{#33244}
> >
> > [email protected],[email protected]
> >
> > # Not skipping CQ checks because original CL landed > 1 day ago.
> >
> > No-Try: True
> > Bug: None
> > Change-Id: I7dbedd3256cb7ff47eb5f8cd46c7c044ed0aa1e0
> > Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/207283
> > Reviewed-by: Mirko Bonadei <[email protected]>
> > Commit-Queue: Mirko Bonadei <[email protected]>
> > Cr-Commit-Position: refs/heads/master@{#33255}
>
> # Not skipping CQ checks because original CL landed > 1 day ago.
>
> Bug: None
> Change-Id: I1bb6186d7f898de82d26f4cd3d8a88014140c518
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/207864
> Reviewed-by: Mirko Bonadei <[email protected]>
> Reviewed-by: Henrik Boström <[email protected]>
> Reviewed-by: Harald Alvestrand <[email protected]>
> Commit-Queue: Harald Alvestrand <[email protected]>
> Cr-Commit-Position: refs/heads/master@{#33283}

Bug: None
Change-Id: I2b09b57c2477e52301ac30ec12ed69f2555ba7f8
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/208021
Reviewed-by: Harald Alvestrand <[email protected]>
Commit-Queue: Harald Alvestrand <[email protected]>
Cr-Commit-Position: refs/heads/master@{#33286}

pc/BUILD.gn

@@ -1044,7 +1044,6 @@ if (rtc_include_tests && !build_with_chromium) {
   rtc_test("peerconnection_unittests") {
     testonly = true
     sources = [
-      "data_channel_integrationtest.cc",
       "data_channel_unittest.cc",
       "dtmf_sender_unittest.cc",
       "ice_server_parsing_unittest.cc",
@@ -1082,8 +1081,6 @@ if (rtc_include_tests && !build_with_chromium) {
       "sdp_serializer_unittest.cc",
       "stats_collector_unittest.cc",
       "test/fake_audio_capture_module_unittest.cc",
-      "test/integration_test_helpers.cc",
-      "test/integration_test_helpers.h",
       "test/test_sdp_strings.h",
       "track_media_info_map_unittest.cc",
       "video_rtp_track_source_unittest.cc",
@@ -1124,24 +1121,19 @@ if (rtc_include_tests && !build_with_chromium) {
       "../api:libjingle_peerconnection_api",
       "../api:media_stream_interface",
       "../api:mock_rtp",
-      "../api:packet_socket_factory",
       "../api:rtc_error",
-      "../api:rtp_transceiver_direction",
       "../api:scoped_refptr",
       "../api/audio:audio_mixer_api",
       "../api/crypto:frame_decryptor_interface",
       "../api/crypto:frame_encryptor_interface",
       "../api/crypto:options",
       "../api/rtc_event_log",
       "../api/rtc_event_log:rtc_event_log_factory",
-      "../api/task_queue",
       "../api/task_queue:default_task_queue_factory",
       "../api/transport:field_trial_based_config",
-      "../api/transport:webrtc_key_value_config",
       "../api/transport/rtp:rtp_source",
       "../api/units:time_delta",
       "../api/video:builtin_video_bitrate_allocator_factory",
-      "../api/video:video_rtp_headers",
       "../call/adaptation:resource_adaptation_test_utilities",
       "../logging:fake_rtc_event_log",
       "../media:rtc_media_config",
@@ -1152,7 +1144,6 @@ if (rtc_include_tests && !build_with_chromium) {
       "../modules/rtp_rtcp:rtp_rtcp_format",
       "../p2p:fake_ice_transport",
       "../p2p:fake_port_allocator",
-      "../p2p:p2p_server_utils",
       "../rtc_base:checks",
       "../rtc_base:gunit_helpers",
       "../rtc_base:ip_address",