Prioritize IPv4 addresses over IPv6 (#3972)

Changes the default RFC3484 address ordering to prefer IPv4 for current
versions of Cobalt. This restores the behavior in prior Cobalt versions.

Test-on-device: True

b/359376180

net/dns/address_sorter_posix.cc

@@ -140,7 +140,13 @@ const AddressSorterPosix::PolicyEntry kDefaultPrecedenceTable[] = {
     // ::/0 -- any
     {{}, 0, 40},
     // ::ffff:0:0/96 -- IPv4 mapped
+#if defined(STARBOARD)
+    // Cobalt currently prioritizes IPv4 addresses higher, as
+    // suggested in section 10.3 of RFC3484
+    {{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF}, 96, 100},
+#else
     {{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF}, 96, 35},
+#endif
     // 2002::/16 -- 6to4
     {{
          0x20,

net/dns/address_sorter_posix_unittest.cc

@@ -386,7 +386,11 @@ TEST_P(AddressSorterPosixSyncOrAsyncTest, Rule6) {
   AddMapping("2001::1", "2001::10");              // Teredo
   const char* const addresses[] = {"2001::1", "::ffff:1234:1", "ff32::1", "::1",
                                    nullptr};
+#if defined(STARBOARD)
+  const int order[] = { 1, 3, 2, 0, -1 };
+#else
   const int order[] = { 3, 2, 1, 0, -1 };
+#endif
   Verify(addresses, order);
 }