ContentType/AgentAPITest.MarkResourceProviderGone is flaky.

I0724 00:38:07.728926  3249 http_connection.hpp:283] Connected with the remote endpoint at http://172.16.10.60:38795/slave(1111)/api/v1/resource_provider
*** Aborted at 1563928687 (unix time) try "date -d @1563928687" if you are using GNU date ***
I0724 00:38:07.730021 27831 slave.cpp:924] Agent terminating
I0724 00:38:07.731081  3250 master.cpp:1295] Agent 8324a471-1cb7-4778-959a-560b074686b8-S0 at slave(1111)@172.16.10.60:38795 (ip-172-16-10-60.ec2.internal) disconnected
I0724 00:38:07.731101  3250 master.cpp:3397] Disconnecting agent 8324a471-1cb7-4778-959a-560b074686b8-S0 at slave(1111)@172.16.10.60:38795 (ip-172-16-10-60.ec2.internal)
I0724 00:38:07.731140  3250 master.cpp:3416] Deactivating agent 8324a471-1cb7-4778-959a-560b074686b8-S0 at slave(1111)@172.16.10.60:38795 (ip-172-16-10-60.ec2.internal)
I0724 00:38:07.731204  3247 hierarchical.cpp:799] Agent 8324a471-1cb7-4778-959a-560b074686b8-S0 deactivated
PC: @     0x7f7a21bf59fc process::UPID::UPID()
*** SIGSEGV (@0x557acd6ed7a1) received by PID 27831 (TID 0x7f7a14040700) from PID 18446744072861177761; stack trace: ***
    @     0x7f79eb0dcde7 (unknown)
    @     0x7f79eb0e4385 JVM_handle_linux_signal
    @     0x7f79eb0d9583 (unknown)
    @     0x7f7a1e2257e0 (unknown)
    @     0x7f7a21bf59fc process::UPID::UPID()
    @     0x7f7a209e6cbb mesos::v1::resource_provider::Driver::send()
    @     0x5579c9704027 mesos::internal::tests::resource_provider::MockResourceProvider<>::connectedDefault()
    @     0x5579c9604b2a testing::internal::FunctionMockerBase<>::UntypedPerformDefaultAction()
    @     0x5579cad9fe83 testing::internal::UntypedFunctionMockerBase::UntypedInvokeWith()
    @     0x5579c9635714 mesos::internal::tests::resource_provider::MockResourceProvider<>::connected()
    @     0x7f7a206a9273 process::AsyncExecutorProcess::execute<>()
    @     0x7f7a206b6b3b _ZNO6lambda12CallableOnceIFvPN7process11ProcessBaseEEE10CallableFnINS_8internal7PartialIZNS1_8dispatchI7NothingNS1_20AsyncExecutorProcessERKSt8functionIFvvEESG_EENS1_6FutureIT_EERKNS1_3PIDIT0_EEMSL_FSI_T1_EOT2_EUlSt10unique_ptrINS1_7PromiseISA_EESt14default_deleteISW_EEOSE_S3_E_JSZ_SE_St12_PlaceholderILi1EEEEEEclEOS3_
    @     0x7f7a21c10ea1 process::ProcessBase::consume()
    @     0x7f7a21c25677 process::ProcessManager::resume()
    @     0x7f7a21c2aae6 _ZNSt6thread11_State_implISt12_Bind_simpleIFZN7process14ProcessManager12init_threadsEvEUlvE_vEEE6_M_runEv
    @     0x7f7a21ee0c7f execute_native_thread_routine
    @     0x7f7a1e21daa1 start_thread
    @     0x7f7a1d1ddc4d clone