Move UBSan warnings from a blacklist to the source

webrtc/rtc_base/ipaddress_unittest.cc

 /*
  *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 654 matching lines @@
   addr2 = IPAddress(kIPv4MappedPublicAddr);
   addr = addr.AsIPv6Address();
   EXPECT_EQ(addr, addr2);
 
   addr = IPAddress(kIPv6PublicAddr);
   addr2 = IPAddress(kIPv6PublicAddr);
   addr = addr.AsIPv6Address();
   EXPECT_EQ(addr, addr2);
 }
 
-// Disabled for UBSan: https://bugs.chromium.org/p/webrtc/issues/detail?id=5491
-#ifdef UNDEFINED_SANITIZER
-#define MAYBE_TestCountIPMaskBits DISABLED_TestCountIPMaskBits
-#else
-#define MAYBE_TestCountIPMaskBits TestCountIPMaskBits
-#endif
-TEST(IPAddressTest, MAYBE_TestCountIPMaskBits) {
+TEST(IPAddressTest, TestCountIPMaskBits) {
   IPAddress mask;
   // IPv4 on byte boundaries
   EXPECT_PRED2(CheckMaskCount, "255.255.255.255", 32);
   EXPECT_PRED2(CheckMaskCount, "255.255.255.0", 24);
   EXPECT_PRED2(CheckMaskCount, "255.255.0.0", 16);
   EXPECT_PRED2(CheckMaskCount, "255.0.0.0", 8);
   EXPECT_PRED2(CheckMaskCount, "0.0.0.0", 0);
 
   // IPv4 not on byte boundaries
   EXPECT_PRED2(CheckMaskCount, "128.0.0.0", 1);
@@ skipping 261 matching lines @@
   IPAddress *paddr1 = &addr1;
   IPAddress *paddr4 = &addr4;
   EXPECT_EQ(*paddr1, *paddr4);
 
   InterfaceAddress addr5(kIPv6LinkLocalAddr,
                          IPV6_ADDRESS_FLAG_TEMPORARY);
   EXPECT_NE(addr1, addr5);
 }
 
 }  // namespace rtc