Revert "Build and test QUIC BBR2 code."

This reverts commit 447ff85d.

Reason for revert: tests timeout in Win.
https://bugs.chromium.org/p/chromium/issues/detail?id=1003278

Original change's description:
> Build and test QUIC BBR2 code.
> 
> Change-Id: I06895589359a77bb771d3b8f8a857ee50398dbec
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1790488
> Commit-Queue: Bin Wu <wub@chromium.org>
> Reviewed-by: Ryan Hamilton <rch@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#695718}

TBR=rch@chromium.org,wub@chromium.org

Change-Id: Ic0f09bb22c6462875295064221dc267ef618dbe2
BUG: 1003278
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1800407Reviewed-by: vitaliii <vitaliii@chromium.org>
Commit-Queue: vitaliii <vitaliii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#695981}

net/BUILD.gn

@@ -1327,18 +1327,6 @@ component("net") {
       "third_party/quiche/src/http2/platform/api/http2_string_utils.h",
       "third_party/quiche/src/quic/core/congestion_control/bandwidth_sampler.cc",
       "third_party/quiche/src/quic/core/congestion_control/bandwidth_sampler.h",
-      "third_party/quiche/src/quic/core/congestion_control/bbr2_drain.cc",
-      "third_party/quiche/src/quic/core/congestion_control/bbr2_drain.h",
-      "third_party/quiche/src/quic/core/congestion_control/bbr2_misc.cc",
-      "third_party/quiche/src/quic/core/congestion_control/bbr2_misc.h",
-      "third_party/quiche/src/quic/core/congestion_control/bbr2_probe_bw.cc",
-      "third_party/quiche/src/quic/core/congestion_control/bbr2_probe_bw.h",
-      "third_party/quiche/src/quic/core/congestion_control/bbr2_probe_rtt.cc",
-      "third_party/quiche/src/quic/core/congestion_control/bbr2_probe_rtt.h",
-      "third_party/quiche/src/quic/core/congestion_control/bbr2_sender.cc",
-      "third_party/quiche/src/quic/core/congestion_control/bbr2_sender.h",
-      "third_party/quiche/src/quic/core/congestion_control/bbr2_startup.cc",
-      "third_party/quiche/src/quic/core/congestion_control/bbr2_startup.h",
       "third_party/quiche/src/quic/core/congestion_control/bbr_sender.cc",
       "third_party/quiche/src/quic/core/congestion_control/bbr_sender.h",
       "third_party/quiche/src/quic/core/congestion_control/cubic_bytes.cc",
@@ -5486,7 +5474,6 @@ test("net_unittests") {
     "third_party/quiche/src/http2/tools/random_util.cc",
     "third_party/quiche/src/http2/tools/random_util.h",
     "third_party/quiche/src/quic/core/congestion_control/bandwidth_sampler_test.cc",
-    "third_party/quiche/src/quic/core/congestion_control/bbr2_simulator_test.cc",
     "third_party/quiche/src/quic/core/congestion_control/bbr_sender_test.cc",
     "third_party/quiche/src/quic/core/congestion_control/cubic_bytes_test.cc",
     "third_party/quiche/src/quic/core/congestion_control/general_loss_algorithm_test.cc",

net/quic/quic_flags_list.h

@@ -49,22 +49,6 @@ QUIC_FLAG(double, FLAGS_quic_bbr_rtt_variation_weight, 0.0f)
 // Congestion window gain for QUIC BBR during PROBE_BW phase.
 QUIC_FLAG(double, FLAGS_quic_bbr_cwnd_gain, 2.0f)
 
-// The default minimum duration for BBRv2-native probes, in milliseconds.
-QUIC_FLAG(int32_t, FLAGS_quic_bbr2_default_probe_bw_base_duration_ms, 2000)
-
-// The default upper bound of the random amount of BBRv2-native probes, in
-// milliseconds.
-QUIC_FLAG(int32_t, FLAGS_quic_bbr2_default_probe_bw_max_rand_duration_ms, 1000)
-
-// The default period for entering PROBE_RTT, in milliseconds.
-QUIC_FLAG(int32_t, FLAGS_quic_bbr2_default_probe_rtt_period_ms, 10000)
-
-// The default loss threshold for QUIC BBRv2, should be a value between 0 and 1.
-QUIC_FLAG(double, FLAGS_quic_bbr2_default_loss_threshold, 0.02)
-
-// The default minimum number of loss marking events to exit STARTUP.
-QUIC_FLAG(int32_t, FLAGS_quic_bbr2_default_startup_full_loss_count, 8)
-
 // If true, adjust congestion window when doing bandwidth resumption in BBR.
 QUIC_FLAG(bool,
           FLAGS_quic_reloadable_flag_quic_fix_bbr_cwnd_in_bandwidth_resumption,