test-thread-breakpoint fails with some gdb version

$ /home/rth/qemu/qemu/tests/guest-debug/run-test.py --gdb /usr/bin/gdb-multiarch --qemu /home/rth/qemu/bld/qemu-arm --qargs "" --bin testthread --test /home/rth/qemu/qemu/tests/tcg/multiarch/gdbstub/test-thread-breakpoint.py
QEMU CMD: /home/rth/qemu/bld/qemu-arm  -g /tmp/tmplhuyh8liqemu-gdbstub/gdbstub.socket testthread
GDB CMD: /usr/bin/gdb-multiarch testthread -q -n -batch -ex 'set confirm off' -ex 'target remote /tmp/tmplhuyh8liqemu-gdbstub/gdbstub.socket' -x /home/rth/qemu/qemu/tests/tcg/multiarch/gdbstub/test-thread-breakpoint.py
0x00010328 in _start ()
ATTACHED: armv7
Breakpoint 1 at 0x10478: file /home/rth/qemu/qemu/tests/tcg/multiarch/testthread.c, line 18.
[New Thread 1.226137]
GDB Exception: <class 'gdb.error'>
All tests complete: 1 failures
$ echo $?
1

The gdb-multiarch in use is "9.2-0ubuntu1~20.04".