Remove the flag which disables non NAT address migration.

net/tools/quic/end_to_end_test.cc

Index: net/tools/quic/end_to_end_test.cc
diff --git a/net/tools/quic/end_to_end_test.cc b/net/tools/quic/end_to_end_test.cc
index ced4c694169766dcf6eb740e07d91496a8dd2467..adeded978e6ab62ba3d6b17b760d89b574c6ec5f 100644
--- a/net/tools/quic/end_to_end_test.cc
+++ b/net/tools/quic/end_to_end_test.cc
@@ -1473,8 +1473,6 @@ class WrongAddressWriter : public QuicPacketWriterWrapper {
 };
 
 TEST_P(EndToEndTest, ConnectionMigrationClientIPChanged) {
-  ValueRestore<bool> old_flag(&FLAGS_quic_disable_non_nat_address_migration,
-                              false);
   ASSERT_TRUE(Initialize());
 
   EXPECT_EQ(kFooResponseBody, client_->SendSynchronousRequest("/foo"));
@@ -1496,8 +1494,6 @@ TEST_P(EndToEndTest, ConnectionMigrationClientIPChanged) {
 }
 
 TEST_P(EndToEndTest, ConnectionMigrationClientPortChanged) {
-  ValueRestore<bool> old_flag(&FLAGS_quic_disable_non_nat_address_migration,
-                              false);
   // Tests that the client's port can change during an established QUIC
   // connection, and that doing so does not result in the connection being
   // closed by the server.