v9_11 dig tsan error

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WARNING: ThreadSanitizer: data race (pid=3642)
  Read of size 1 at 0x7f20e95d1cd4 by main thread:
    #0 isc__app_ctxrun /builds/isc-projects/bind9/lib/isc/unix/app.c:746:34 (libisc.so.1107+0x55d7c)
    #1 isc__app_run /builds/isc-projects/bind9/lib/isc/unix/app.c:756:10 (libisc.so.1107+0x55f2a)
    #2 isc_app_run /builds/isc-projects/bind9/lib/isc/unix/./../app_api.c:207:12 (libisc.so.1107+0x574a1)
    #3 dig_startup /builds/isc-projects/bind9/bin/dig/dig.c:2294:2 (dig+0x4bed45)
    #4 main /builds/isc-projects/bind9/bin/dig/dig.c:2326:2 (dig+0x4bee41)

  Previous write of size 1 at 0x7f20e95d1cd4 by thread T1 (mutexes: write M1074):
    #0 isc__app_block /builds/isc-projects/bind9/lib/isc/unix/app.c:936:23 (libisc.so.1107+0x56522)
    #1 isc_app_block /builds/isc-projects/bind9/lib/isc/unix/./../app_api.c:260:2 (libisc.so.1107+0x57717)
    #2 get_address /builds/isc-projects/bind9/bin/dig/dighost.c:4437:3 (dig+0x4ca090)
    #3 send_tcp_connect /builds/isc-projects/bind9/bin/dig/dighost.c:3011:11 (dig+0x4ca371)
    #4 do_lookup /builds/isc-projects/bind9/bin/dig/dighost.c:4493:4 (dig+0x4c935f)
    #5 start_lookup /builds/isc-projects/bind9/bin/dig/dighost.c:2043:4 (dig+0x4c75b0)
    #6 onrun_callback /builds/isc-projects/bind9/bin/dig/dighost.c:4508:2 (dig+0x4cb054)
    #7 dispatch /builds/isc-projects/bind9/lib/isc/task.c:1157:7 (libisc.so.1107+0x50785)
    #8 run /builds/isc-projects/bind9/lib/isc/task.c:1331:2 (libisc.so.1107+0x4d6d9)

  Location is global 'isc_g_appctx' of size 200 at 0x7f20e95d1c80 (libisc.so.1107+0x000000093cd4)

  Mutex M1074 (0x000000f39b98) created at:
    #0 pthread_mutex_init <null> (dig+0x430cbd)
    #1 isc__mutex_init /builds/isc-projects/bind9/lib/isc/pthreads/mutex.c:287:8 (libisc.so.1107+0x72317)
    #2 setup_libs /builds/isc-projects/bind9/bin/dig/dighost.c:1664:11 (dig+0x4c6c2b)
    #3 dig_setup /builds/isc-projects/bind9/bin/dig/dig.c:2267:2 (dig+0x4bc6c5)
    #4 main /builds/isc-projects/bind9/bin/dig/dig.c:2324:2 (dig+0x4bee2e)

  Thread T1 'isc-worker0000' (tid=3657, running) created by main thread at:
    #0 pthread_create <null> (dig+0x42f73b)
    #1 isc_thread_create /builds/isc-projects/bind9/lib/isc/pthreads/thread.c:60:8 (libisc.so.1107+0x72488)
    #2 isc__taskmgr_create /builds/isc-projects/bind9/lib/isc/task.c:1468:7 (libisc.so.1107+0x4d5e5)
    #3 isc_taskmgr_create /builds/isc-projects/bind9/lib/isc/task.c:2109:11 (libisc.so.1107+0x4f537)
    #4 setup_libs /builds/isc-projects/bind9/bin/dig/dighost.c:1634:11 (dig+0x4c6aa6)
    #5 dig_setup /builds/isc-projects/bind9/bin/dig/dig.c:2267:2 (dig+0x4bc6c5)
    #6 main /builds/isc-projects/bind9/bin/dig/dig.c:2324:2 (dig+0x4bee2e)

SUMMARY: ThreadSanitizer: data race /builds/isc-projects/bind9/lib/isc/unix/app.c:746:34 in isc__app_ctxrun
==================