The gdb-fedora-s390x buildbot fails, alternatively with checkout problems and an actual failure.

For an example of the latter, see https://builder.sourceware.org/buildbot/#/builders/75/builds/839 :
...
Ran 3640 unit tests, 1 failed
(gdb) PASS: gdb.gdb/unittest.exp: no executable loaded: maintenance selftest, ran some tests
FAIL: gdb.gdb/unittest.exp: no executable loaded: maintenance selftest, failed none
...

In more detail:
...
Running selftest arm-record.
Process record and replay target doesn't support syscall number -2036195
Process record does not support instruction 0x7f70ee1d at address 0x0.
Self test failed: self-test failed at ../../binutils-gdb/gdb/arm-tdep.c:14482
...

The failure is in the "ret == 0" selftest:
...
    static const uint16_t insns[] = {
      /* 1d ee 70 7f     mrc    15, 0, r7, cr13, cr0, {3} */
      0xee1d, 0x7f70,
    };

    enum bfd_endian endian = gdbarch_byte_order_for_code (arm_record.gdbarch);
    instruction_reader_thumb reader (endian, insns);
    int ret = decode_insn (reader, &arm_record, THUMB2_RECORD,
                           THUMB2_INSN_SIZE_BYTES);

    SELF_CHECK (ret == 0);
    SELF_CHECK (arm_record.mem_rec_count == 0);
    SELF_CHECK (arm_record.reg_rec_count == 1);
    SELF_CHECK (arm_record.arm_regs[0] == 7);
...

Note that the:
...
Process record does not support instruction 0x7f70ee1d at address 0x0.
...
message corresponds to the insns array.  Hm, process record seems to think that it's one insn, while in fact there are two.