Remove QuicEnableDefaultEnabledVersions

Now that cl/290818515  has landed, we no longer need QuicEnableDefaultEnabledVersions() to ensure some versions are enabled, so we're removing it.

NO_BUG=test-only cleanup
gfe-relnote: n/a, test-only change
PiperOrigin-RevId: 290845205
Change-Id: Ib18342e5dab32040a795a30dd3a311efc3dbfb2d

quic/quartc/quartc_multiplexer_test.cc

diff --git a/quic/quartc/quartc_multiplexer_test.cc b/quic/quartc/quartc_multiplexer_test.cc
index 88fbf59..ffffb97 100644
--- a/quic/quartc/quartc_multiplexer_test.cc
+++ b/quic/quartc/quartc_multiplexer_test.cc
@@ -200,7 +200,6 @@
             simulator_.GetRandomGenerator(),
             &server_multiplexer_,
             quic::QuartcSessionConfig())) {
-    quic::test::QuicEnableDefaultEnabledVersions();
     // TODO(b/134175506): Remove when IETF QUIC supports receive timestamps.
     SetQuicReloadableFlag(quic_enable_version_t099, false);
   }

quic/quartc/quartc_session_test.cc

diff --git a/quic/quartc/quartc_session_test.cc b/quic/quartc/quartc_session_test.cc
index d2eb9eb..cab7e60 100644
--- a/quic/quartc/quartc_session_test.cc
+++ b/quic/quartc/quartc_session_test.cc
@@ -54,7 +54,6 @@
   ~QuartcSessionTest() override {}
 
   void Init(bool create_client_endpoint = true) {
-    quic::test::QuicEnableDefaultEnabledVersions();
     // TODO(b/134175506): Remove when IETF QUIC supports receive timestamps.
     SetQuicReloadableFlag(quic_enable_version_t099, false);
 

quic/test_tools/quic_test_utils.cc

diff --git a/quic/test_tools/quic_test_utils.cc b/quic/test_tools/quic_test_utils.cc
index e033ac5..b83b2ba 100644
--- a/quic/test_tools/quic_test_utils.cc
+++ b/quic/test_tools/quic_test_utils.cc
@@ -786,21 +786,6 @@
   return AllSupportedTransportVersions().back();
 }
 
-void QuicEnableDefaultEnabledVersions() {
-  if (!GetQuicReloadableFlag(quic_testonly_default_false)) {
-    // If quic_testonly_default_false is false, then we are not in a mode where
-    // all flags have been flipped to true.
-    return;
-  }
-  static_assert(QUICHE_ARRAYSIZE(kSupportedTransportVersions) == 6u,
-                "Supported versions out of sync");
-  SetQuicReloadableFlag(quic_disable_version_q050, false);
-  SetQuicReloadableFlag(quic_disable_version_q049, false);
-  SetQuicReloadableFlag(quic_disable_version_q048, false);
-  SetQuicReloadableFlag(quic_disable_version_q046, false);
-  SetQuicReloadableFlag(quic_disable_version_q043, false);
-}
-
 QuicEncryptedPacket* ConstructEncryptedPacket(
     QuicConnectionId destination_connection_id,
     QuicConnectionId source_connection_id,

quic/test_tools/quic_test_utils.h

diff --git a/quic/test_tools/quic_test_utils.h b/quic/test_tools/quic_test_utils.h
index 94f7ff1..7ee7df5 100644
--- a/quic/test_tools/quic_test_utils.h
+++ b/quic/test_tools/quic_test_utils.h
@@ -71,9 +71,6 @@
 // TODO(nharper): Remove this function when it is no longer used.
 QuicTransportVersion QuicTransportVersionMin();
 
-// Ensures that not all versions are disabled when all flags are set to true.
-void QuicEnableDefaultEnabledVersions();
-
 // Create an encrypted packet for testing.
 // If versions == nullptr, uses &AllSupportedVersions().
 // Note that the packet is encrypted with NullEncrypter, so to decrypt the