Crash during normal run

I had a crash happen - it looked like there were about 60 iterations of the below output before the crash.

```
[Reminders ▶ Taskwarrior] Figure out why puppet-master service won't start
[Taskwarrior] sync
[Taskwarrior] reminderID:482D7EAA-6901-4BAB-8117-945700669B76 export
```

Crash Report

```
2020-07-05 18:48:46.309 task-reminders-sync[1285:11023] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Failed to set posix_spawn_file_actions for fd -1 at index 0 with errno 9'
*** First throw call stack:
(
0 CoreFoundation 0x00007fff2fd55be7 __exceptionPreprocess + 250
1 libobjc.A.dylib 0x00007fff68b2d5bf objc_exception_throw + 48
2 Foundation 0x00007fff32416034 -[NSConcreteTask launchWithDictionary:error:] + 5300
3 task-reminders-sync 0x0000000108fae79c $s12Repositories21TaskwarriorRepositoryC04execB033_34B1B378C6FD518C2F80C60344E1C084LL4args5input10Foundation4DataVSgSaySSG_6Models4TaskCSgtFTf4nnd_n + 1756
4 task-reminders-sync 0x0000000108fa9242 $s12Repositories21TaskwarriorRepositoryC05fetchB4Task6filter6Models0E0CSgSS_tF + 82
5 task-reminders-sync 0x0000000108fa95d3 $s12Repositories21TaskwarriorRepositoryC08upsertToB0yy6Models4TaskCF + 131
6 task-reminders-sync 0x0000000108fb3851 $s4Sync17RemindersObserverC12storeChanged12notificationy10Foundation12NotificationV_tFySo10EKReminderCXEfU_yycfU_ + 385
7 task-reminders-sync 0x0000000108fb3889 $sIeg_IeyB_TR + 25
8 libdispatch.dylib 0x00007fff69c7a6c4 _dispatch_call_block_and_release + 12
9 libdispatch.dylib 0x00007fff69c7b658 _dispatch_client_callout + 8
10 libdispatch.dylib 0x00007fff69c86cab _dispatch_main_queue_callback_4CF + 936
11 CoreFoundation 0x00007fff2fd18f11 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 9
12 CoreFoundation 0x00007fff2fcd8d17 __CFRunLoopRun + 2028
13 CoreFoundation 0x00007fff2fcd7ece CFRunLoopRunSpecific + 462
14 Foundation 0x00007fff323701c8 -[NSRunLoop(NSRunLoop) runMode:beforeDate:] + 212
15 Foundation 0x00007fff32422c6f -[NSRunLoop(NSRunLoop) run] + 76
16 task-reminders-sync 0x0000000108fb194f main + 127
17 libdyld.dylib 0x00007fff69cd4cc9 start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
[1] 1285 abort ./task-reminders-sync
```

Start at TaskwarriorRepository.exec, the entry point shown in the crash stack, then trace calls through fetchTask, upsertToTask, and RemindersObserver.storeChanged. Reproduce a normal run with repeated reminder sync activity and determine why process launch fails; done means the run completes without the reported crash.

Written by the indexing model from the issue text.