"exception raised while parsing perf output" with "branches:u: tr strt"

[ednolan]

With Ubuntu 24.04, magic-trace 1.2.4 fails to parse the perf data it records for /bin/true:

root@eddie-beman-server:~# /home/eddie/magic-trace --version
v1.2.4
root@eddie-beman-server:~# perf --version
perf version 6.8.12
root@eddie-beman-server:~# head -n 1 /etc/os-release
PRETTY_NAME="Ubuntu 24.04.1 LTS"
root@eddie-beman-server:~# head -n 5 /proc/cpuinfo
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 190
model name      : Intel(R) N150
root@eddie-beman-server:~# MAGIC_TRACE_DEBUG=1 /home/eddie/magic-trace run -z-print-perf-commands /bin/true
perf record -o /tmp/magic_trace.tmp.2d760e/perf.data --timestamp --event=intel_pt/cyc=1,cyc_thresh=1,mtc_period=0/u --per-thread -t 377283 --snapshot=e
[ Snapshot taken. ]
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.070 MB /tmp/magic_trace.tmp.2d760e/perf.data ]
[ Finished recording. ]
[ Decoding, this takes a while... ]
Warning: Debug info is unavailable, so filenames and line numbers will not be available in the trace.
See https://github.com/janestreet/magic-trace/wiki/Compiling-code-for-maximum-compatibility-with-magic-trace for more info.
perf script -i /tmp/magic_trace.tmp.2d760e/perf.data --ns --itrace=bep -F pid,tid,time,flags,ip,addr,sym,symoff,synth,dso,event,period --dlfilter /tmp/magic_trace.tmp.2d760e/perf_dlfilter.so
(monitor.ml.Error
 ("BUG: exception raised while parsing perf output. Please report this to https://github.com/janestreet/magic-trace/issues/"
  (exn Not_found)
  (perf_output
   (" 377283/377283  1693318.312267580:          1                                 branches:u:   tr strt           (D)                 0 [unknown] ([unknown]) =>     73e8caac0540 [unknown] (/usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)")))
 ("Raised at Base__Error.raise in file \"src/error.ml\" (inlined), line 9, characters 14-30"
  "Called from Base__Error.raise_s in file \"src/error.ml\", line 10, characters 19-40"
  "Called from Async_kernel__Pipe.map.(fun) in file \"src/pipe.ml\", line 1066, characters 65-70"
  "Called from Async_kernel__Job_queue.run_jobs in file \"src/job_queue.ml\", line 180, characters 6-47"
  "Caught by monitor Monitor.protect"))