[BUG] Lock order inversion: m_GroupLock vs m_ConnectionLock

[maxsharabayko]

WARNING: ThreadSanitizer: lock-order-inversion (potential deadlock) (pid=4255)
  Cycle in lock order graph: M628 (0x7ba8000231b0) => M686 (0x7b540001fe08) => M628

  Mutex M686 (m_GroupLock) acquired here while holding mutex M628 (m_ConnectionLock) in thread T6:
    #0 pthread_mutex_lock ../../../../src/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:4240 (libtsan.so.0+0x53908)
    #1 srt::sync::Mutex::lock() .../srt-xtransmit/submodule/srt/srtcore/sync_posix.cpp:220 (srt-xtransmit+0x3e8865)
    #2 srt::sync::ScopedLock::ScopedLock(srt::sync::Mutex&) .../srt-xtransmit/submodule/srt/srtcore/sync.h:354 (srt-xtransmit+0x2b2889)    <-- m_GroupLock
    #3 srt::CUDT::makeMePeerOf(int, SRT_GROUP_TYPE, unsigned int) .../srt-xtransmit/submodule/srt/srtcore/core.cpp:3340 (srt-xtransmit+0x302000)
    #4 srt::CUDT::interpretGroup(int const*, unsigned long, int) .../srt-xtransmit/submodule/srt/srtcore/core.cpp:3238 (srt-xtransmit+0x30153f)
    #5 srt::CUDT::interpretSrtHandshake(srt::CHandShake const&, srt::CPacket const&, unsigned int*, unsigned long*) .../srt-xtransmit/submodule/srt/srtcore/core.cpp:2923 (srt-xtransmit+0x2fe2fa)
    #6 srt::CUDT::acceptAndRespond(srt::sockaddr_any const&, srt::sockaddr_any const&, srt::CPacket const&, srt::CHandShake&) .../srt-xtransmit/submodule/srt/srtcore/core.cpp:5832 (srt-xtransmit+0x311616)
    #7 srt::CUDTUnited::newConnection(int, srt::sockaddr_any const&, srt::CPacket const&, srt::CHandShake&, int&, srt::CUDT*&) .../srt-xtransmit/submodule/srt/srtcore/api.cpp:628 (srt-xtransmit+0x291779)
    #8 srt::CUDT::processConnectRequest(srt::sockaddr_any const&, srt::CPacket&) .../srt-xtransmit/submodule/srt/srtcore/core.cpp:11249 (srt-xtransmit+0x32eb10)
    #9 srt::CRcvQueue::worker_ProcessConnectionRequest(srt::CUnit*, srt::sockaddr_any const&) .../srt-xtransmit/submodule/srt/srtcore/queue.cpp:1437 (srt-xtransmit+0x388a30)
    #10 srt::CRcvQueue::worker(void*) .../srt-xtransmit/submodule/srt/srtcore/queue.cpp:1271 (srt-xtransmit+0x387a27)

    Hint: use TSAN_OPTIONS=second_deadlock_stack=1 to get more informative warning message

  Mutex M628 (m_ConnectionLock) acquired here while holding mutex M686 (m_GroupLock) in main thread:
    #0 pthread_mutex_lock ../../../../src/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:4240 (libtsan.so.0+0x53908)
    #1 srt::sync::Mutex::lock() .../srt-xtransmit/submodule/srt/srtcore/sync_posix.cpp:220 (srt-xtransmit+0x3e8865)
    #2 srt::sync::ScopedLock::ScopedLock(srt::sync::Mutex&) .../srt-xtransmit/submodule/srt/srtcore/sync.h:354 (srt-xtransmit+0x2b2889)
    #3 srt::CUDT::getOpt(SRT_SOCKOPT, void*, int&) .../srt-xtransmit/submodule/srt/srtcore/core.cpp:459 (srt-xtransmit+0x2ebaaa)   <-- m_ConnectionLock;
    #4 srt::CUDTGroup::getOpt(SRT_SOCKOPT, void*, int&) .../srt-xtransmit/submodule/srt/srtcore/group.cpp:789 (srt-xtransmit+0x3b2126)
    #5 srt::CUDT::getsockopt(int, int, SRT_SOCKOPT, void*, int*) .../srt-xtransmit/submodule/srt/srtcore/api.cpp:3877 (srt-xtransmit+0x2a8d78)
    #6 srt_getsockflag .../srt-xtransmit/submodule/srt/srtcore/srt_c_api.cpp:168 (srt-xtransmit+0x3a3e3f)
    #7 operator() .../srt-xtransmit/xtransmit/srt_socket.cpp:350 (srt-xtransmit+0x123dc2)
    #8 xtransmit::socket::srt::print_negotiated_config[abi:cxx11](int) .../srt-xtransmit/xtransmit/srt_socket.cpp:360 (srt-xtransmit+0x1240fa)
    #9 xtransmit::socket::srt_group::accept() .../srt-xtransmit/xtransmit/srt_socket_group.cpp:431 (srt-xtransmit+0x157f69)
    #10 xtransmit::create_connection(std::vector<UriParser, std::allocator<UriParser> > const&, std::shared_ptr<xtransmit::socket::isocket>&) .../srt-xtransmit/xtransmit/misc.cpp:37 (srt-xtransmit+0xe482d)
    #11 xtransmit::common_run(std::vector<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > const&, xtransmit::stats_config const&, xtransmit::conn_config const&, std::atomic<bool> const&, std::function<void (std::shared_ptr<xtransmit::socket::isocket>, std::function<void (int)> const&, std::atomic<bool> const&)>&) .../srt-xtransmit/xtransmit/misc.cpp:197 (srt-xtransmit+0xe5093)
    #12 xtransmit::receive::run(std::vector<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > const&, xtransmit::receive::config const&, std::atomic<bool> const&) .../srt-xtransmit/xtransmit/receive.cpp:142 (srt-xtransmit+0xf9d71)
    #13 main .../srt-xtransmit/xtransmit/xtransmit-app.cpp:231 (srt-xtransmit+0x182b2e)

SRT v1.5.3+ (eecc176).

Introduced in PR #2912.

To Reproduce

Build srt-xtransmit with Thread Sanitizer (-DCMAKE_CXX_FLAGS='-fsanitize=thread' -DWITH_COMPILER_TYPE=clang).
The error is reported on the receiver.

srt-xtransmit generate srt://172.27.16.247:4200 srt://172.27.16.247:5200 --enable-metrics --loglevel note --sendrate 5Mbps --num 2000 --reconnect --concurrent-streams 2 --maxconns 6 

srt-xtransmit receive srt://:4200 srt://:5200 --loglevel note --enable-metrics --reconnect --maxconns 6 --concurrent-streams 2

Epic #1610 – Core Synchronization Issues.