Merge bitcoin#31580: test: Remove non-portable IPv6 test

d871d77 test: Remove non-portable IPv6 test (Hennadii Stepanov)

Pull request description:

  On Illumos-based systems, such as OpenIndiana and OmniOS, the assumption that "the default zone ID of 0 can be omitted for the default scope" is incorrect. As a result, `getaddrinfo("fe80::1%0", ...)` returns the `EAI_NONAME` error instead of resolving to "fe80::1".

  See: https://www.illumos.org/man/3SOCKET/getaddrinfo.

  This PR removes the problematic code introduced in bitcoin#19951.

ACKs for top commit:
  fanquake:
    ACK d871d77

Tree-SHA512: 2ef5c22f826d16661deb1d6d005cbda64179e8b83be43d3d6ac51caff02187cf224355c9da144ff110a6ae2cb68f0338ea9b62af8e0f9f1014a518cf9dad6ab5

src/test/net_tests.cpp

@@ -194,13 +194,6 @@ BOOST_AUTO_TEST_CASE(cnetaddr_basic)
     BOOST_CHECK(!addr.IsBindAny());
     BOOST_CHECK_EQUAL(addr.ToStringAddr(), scoped_addr);
 
-    // Test that the delimiter "%" and default zone id of 0 can be omitted for the default scope.
-    addr = LookupHost(link_local + "%0", false).value();
-    BOOST_REQUIRE(addr.IsValid());
-    BOOST_REQUIRE(addr.IsIPv6());
-    BOOST_CHECK(!addr.IsBindAny());
-    BOOST_CHECK_EQUAL(addr.ToStringAddr(), link_local);
-
     // TORv2, no longer supported
     BOOST_CHECK(!addr.SetSpecial("6hzph5hv6337r6p2.onion"));