How to reproduce:
1. Open the attached DebugRepro project
2. Open SampleScene in Assets/Scenes folder
3. Open "repro" script in Visual Studio which is located in the Assets folder
4. In Visual Studio Attach To Unity and Play
5. While the debugger is getting ready repeatedly press F9 on the Dictionary variable to set or remove a breakpoint

Expected result: Breakpoint in the script is hit
Actual result: Unity crashes

Reproducible with: 2017.2.3p4, 2017.3.2f1, 2017.4.11f1, 2018.1.9f2, 2018.2.8f1, 2018.3.0b2, 2019.1.0a1

Note: There are multiple stack traces most frequent one seems to be set_bp_in_method_cb