Internal crash in Windows 10 1909

**Describe the bug**
Crashes immediately at startup when trying to run my 32-bit complex app.

**To Reproduce**

> drmemory -pause_at_assert -light -visual_studio -- Y:\Release\myapp.exe
```
Dr. Memory version 2.3.18351
Running "Y:\Release\myapp.exe"
Using system call file C:\Users\Owner\AppData\Roaming\Dr. Memory\symcache\syscalls_wow64.txt

WARNING: application exited with abnormal code 0xffffffff
```

> drmemory -debug -dr_debug -pause_at_assert -light -visual_studio -- Y:\Release\myapp.exe
```

Dr. Memory version 2.3.18351
Running "Y:\Release\myapp.exe"
Using system call file C:\Users\Owner\AppData\Roaming\Dr. Memory\symcache\syscalls_wow64.txt
WARNING: application exited with abnormal code 0xc0000005
```

At one point I was able to get it to tell me that this 0xC0000005 occurred during `memset` inside the `ntdll.dll` startup code, but I haven't been able to reproduce that output; it's just crashing now.

Probably also of note:

> drmemory -light -visual_studio -- C:\windows\notepad.exe
```
Dr. Memory version 2.3.18351
Running "c:\windows\notepad.exe"
Using system call file C:\Users\Owner\AppData\Roaming\Dr. Memory\symcache\syscalls_x64.txt
ERROR: Failed to find "main" for limiting memory dump

Fetching 1 symbol files...
[1/1] Fetching symbols for C:\WINDOWS\System32\msvcp_win.dll
Fetched 1 symbol files successfully
WARNING: application exited with abnormal code 0xffffffff
```

Notepad does run ok with `-debug -dr_debug` specified.

FYI both the app and Notepad start up successfully using `drrun`.