gh-119461: Fix ThreadedVSOCKSocketStreamTest

[vstinner]

Add socket.VMADDR_CID_LOCAL constant.

Fix ThreadedVSOCKSocketStreamTest: if get_cid() returns the host address or the "any" address, use the local communication address (loopback): VMADDR_CID_LOCAL.

On Linux 6.9, apparently, the /dev/vsock device is now available but get_cid() returns VMADDR_CID_ANY (-1).

• Issue: test_socket: testStream() fails on Fedora Rawhide #119461

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @vstinner for commit d81cb0b 🤖

If you want to schedule another build, you need to add the 🔨 test-with-buildbots label again.

[vstinner]

buildbot/AMD64 Arch Linux TraceRefs PR: test failure looks unrelated:

test_basic_multiple_interpreters_reset_each (test.test_import.SinglephaseInitTests.test_basic_multiple_interpreters_reset_each) ... python: Objects/object.c:195: _PyRefchain_Remove: Assertion `value == REFCHAIN_VALUE' failed. Fatal Python error: Aborted Current thread 0x00007f3c8619e740 (most recent call first): File "<string>", line 54 in <module> Extension modules: _testinternalcapi, _testmultiphase, _testcapi (total: 3) 

buildbot/AMD64 Arch Linux Usan PR: build failure is unrelated.

Objects/object.c:1019:16: runtime error: call to function long_hash through pointer to incorrect function type 'long (*)(struct _object *)' 

buildbot/ARM64 Windows Non-Debug PR: test_cext failure is unrelated.

 extension.c(50): warning C4116: unnamed type definition in parentheses extension.c(50): error C2059: syntax error: 'static_assert' extension.c(50): error C2059: syntax error: ')' extension.c(50): error C2059: syntax error: ',' extension.c(52): error C2059: syntax error: 'return' extension.c(53): error C2059: syntax error: '}' extension.c(69): error C2065: '_testcext_slots': undeclared identifier extension.c(63): warning C4047: 'initializing': 'PyModuleDef_Slot *' differs in levels of indirection from 'int' error: command 'C:\\Program Files\\Microsoft Visual Studio\\2022\\Community\\VC\\Tools\\MSVC\\14.31.31103\\bin\\HostX86\\ARM64\\cl.exe' failed with exit code 2 [end of output] note: This error originates from a subprocess, and is likely not a problem with pip. ERROR: Failed building wheel for internal-test-c11-cext 

[bedevere-app]

GH-119479 is a backport of this pull request to the 3.13 branch.