Steps to reproduce:
1) Open the attached project.
2) Make sure the Console tab is visible.
3) Enable Collapse for log messages.
4) Enter play mode.
5) Wait for around a minute.
- After a short while, collapsed assert messages start appearing in the Console.
5) Click on the assert message in the Console.

Unity crashes in ves_icall_System_Array_GetLowerBound.
This does not occur when .NET 4.6 compatibility is enabled. Sometimes the crash occurs without even clicking on the assert message.
This does not occur on Windows.

Reproducible versions:
2018.1.0a7, 2017.1.1f1

Reproduced on:
Macbook Pro 2015 running macOS 10.12.6

Did not reproduce on:
Windows 10

Resolution: This works in the new scripting runtime. The issue appears to be with the Mono JIT handling of the unsafe code in the test case, and it's unlikely we will ever fix this in the old Mono.