Fix undefined behavior in the destructor for OpMsgFuzzerFixture

OpMsgFuzzerFixture::~OpMsgFuzzerFixture() {

    CollectionShardingStateFactory::clear(_serviceContext);

    {

        auto clientGuard = _clientStrand->bind();

        auto opCtx = _serviceContext->makeOperationContext(clientGuard.get());

        Lock::GlobalLock glk(opCtx.get(), MODE_X);

        auto databaseHolder = DatabaseHolder::get(opCtx.get());

        databaseHolder->closeAll(opCtx.get());

    }

    shutdownGlobalStorageEngineCleanly(_serviceContext);

}

void ClientStrand::_setCurrent() noexcept {

    invariant(_isBound.load());

    invariant(_client);

    LOGV2_DEBUG(

        5127801, kDiagnosticLogLevel, "Setting the Client", "client"_attr = _client->desc());

    // Set the Client for this thread so calls to Client::getCurrent() works as expected.

    Client::setCurrent(std::move(_client));

    // Set up the thread name.

    _oldThreadName = ThreadName::set(ThreadContext::get(), _threadName);

    if (_oldThreadName) {

        LOGV2_DEBUG(5127802, kDiagnosticLogLevel, "Set thread name", "name"_attr = *_threadName);

    }

}

[cpp_libfuzzer_test:op_msg_fuzzer] SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior src/mongo/util/decorable.h:84:28 in

[cpp_libfuzzer_test:op_msg_fuzzer] AddressSanitizer:DEADLYSIGNAL

[cpp_libfuzzer_test:op_msg_fuzzer] =================================================================

[cpp_libfuzzer_test:op_msg_fuzzer] ==12365==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000018 (pc 0x55aea54da19e bp 0x7ffca099be90 sp 0x7ffca099be70 T0)

[cpp_libfuzzer_test:op_msg_fuzzer] ==12365==The signal is caused by a READ memory access.

[cpp_libfuzzer_test:op_msg_fuzzer] ==12365==Hint: address points to the zero page.

[cpp_libfuzzer_test:op_msg_fuzzer]     #0 0x55aea54da19d in std::__uniq_ptr_impl<unsigned char, std::default_delete<unsigned char []> >::_M_ptr() const /opt/mongodbtoolchain/revisions/0d5a071f1db663c050a1d7f330c13f46e62d6d4f/stow/gcc-v3.ulc/lib/gcc/x86_64-mongodb-linux/8.5.0/../../../../include/c++/8.5.0/bits/unique_ptr.h:150:42

[cpp_libfuzzer_test:op_msg_fuzzer]     #1 0x55aeb36890a3 in std::unique_ptr<unsigned char [], std::default_delete<unsigned char []> >::get() const /opt/mongodbtoolchain/revisions/0d5a071f1db663c050a1d7f330c13f46e62d6d4f/stow/gcc-v3.ulc/lib/gcc/x86_64-mongodb-linux/8.5.0/../../../../include/c++/8.5.0/bits/unique_ptr.h:598:21

[cpp_libfuzzer_test:op_msg_fuzzer]     #2 0x55aeb36890a3 in mongo::DecorationContainer<mongo::ThreadContext>::getDecoration(mongo::DecorationContainer<mongo::ThreadContext>::DecorationDescriptor) /data/mci/cf4c5d480d66775786e7d4ad6010fa16/src/src/mongo/util/decoration_container.h:168

[cpp_libfuzzer_test:op_msg_fuzzer]     #3 0x55aeb367f3e8 in mongo::(anonymous namespace)::ThreadNameSconce& mongo::DecorationContainer<mongo::ThreadContext>::getDecoration<mongo::(anonymous namespace)::ThreadNameSconce>(mongo::DecorationContainer<mongo::ThreadContext>::DecorationDescriptorWithType<mongo::(anonymous namespace)::ThreadNameSconce>) /data/mci/cf4c5d480d66775786e7d4ad6010fa16/src/src/mongo/util/decoration_container.h:183:33

[cpp_libfuzzer_test:op_msg_fuzzer]     #4 0x55aeb367f3e8 in mongo::Decorable<mongo::ThreadContext>::Decoration<mongo::(anonymous namespace)::ThreadNameSconce>::operator()(mongo::ThreadContext&) const /data/mci/cf4c5d480d66775786e7d4ad6010fa16/src/src/mongo/util/decorable.h:80

[cpp_libfuzzer_test:op_msg_fuzzer]     #5 0x55aeb367f3e8 in mongo::Decorable<mongo::ThreadContext>::Decoration<mongo::(anonymous namespace)::ThreadNameSconce>::operator()(mongo::ThreadContext*) const /data/mci/cf4c5d480d66775786e7d4ad6010fa16/src/src/mongo/util/decorable.h:84

[cpp_libfuzzer_test:op_msg_fuzzer]     #6 0x55aeb367e2b8 in mongo::ThreadName::set(boost::intrusive_ptr<mongo::ThreadContext>, boost::intrusive_ptr<mongo::ThreadName>) /data/mci/cf4c5d480d66775786e7d4ad6010fa16/src/src/mongo/util/concurrency/thread_name.cpp:204:20

[cpp_libfuzzer_test:op_msg_fuzzer]     #7 0x55aeb2be4801 in mongo::ClientStrand::_setCurrent() /data/mci/cf4c5d480d66775786e7d4ad6010fa16/src/src/mongo/db/client_strand.cpp:70:22

[cpp_libfuzzer_test:op_msg_fuzzer]     #8 0x55aea5292ef8 in mongo::ClientStrand::bind() /data/mci/cf4c5d480d66775786e7d4ad6010fa16/src/src/mongo/db/client_strand.h:151:16

[cpp_libfuzzer_test:op_msg_fuzzer]     #9 0x55aea5292ef8 in mongo::OpMsgFuzzerFixture::~OpMsgFuzzerFixture() /data/mci/cf4c5d480d66775786e7d4ad6010fa16/src/src/mongo/db/op_msg_fuzzer_fixture.cpp:133

[cpp_libfuzzer_test:op_msg_fuzzer]     #10 0x7f90028bc160 in __run_exit_handlers /build/glibc-S9d2JN/glibc-2.27/stdlib/exit.c:108

[cpp_libfuzzer_test:op_msg_fuzzer]     #11 0x7f90028bc259 in exit /build/glibc-S9d2JN/glibc-2.27/stdlib/exit.c:139

[cpp_libfuzzer_test:op_msg_fuzzer]     #12 0x55aea5129b40 in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) /data/mci/dfb39050aa31abca2c40371c920c586e/toolchain-builder/tmp/build-llvm.sh-GjU/llvm/projects/compiler-rt/lib/fuzzer/FuzzerDriver.cpp:768:5

[cpp_libfuzzer_test:op_msg_fuzzer]     #13 0x55aea5152462 in main /data/mci/dfb39050aa31abca2c40371c920c586e/toolchain-builder/tmp/build-llvm.sh-GjU/llvm/projects/compiler-rt/lib/fuzzer/FuzzerMain.cpp:20:10

[cpp_libfuzzer_test:op_msg_fuzzer]     #14 0x7f900289abf6 in __libc_start_main /build/glibc-S9d2JN/glibc-2.27/csu/../csu/libc-start.c:310

[cpp_libfuzzer_test:op_msg_fuzzer]     #15 0x55aea5106029 in _start (/data/mci/cf4c5d480d66775786e7d4ad6010fa16/src/build/install/bin/op_msg_fuzzer+0x32538029)