Steps to reproduce the issue:
1. Open attached project.
2. Open scene named "CrashScene".
3. Enter the Play mode.
4. Press "Delete Mesh" button in the "Game" window.

Actual result:
The Editor crashes when trying to destroy the mesh.

Expected result:
The Editor should not crash when trying to destroy the mesh.

Reproduced with:
5.4.0b25, 5.4.0f3.
With 5.5.0a5 the Editor freezes, but the crash does not occur.

Cannot reproduce with:
5.1.5f1, 5.2.5f1, 5.3.4p4, 5.3.5f1, 5.3.6p2.

Note:
Open script named "MeshCrash", temporary delete this line of code: "DestroyImmediate(m_Mesh);", save the changes and notice that the issue is no longer reproducible.
If "Clear()" is called prior to "Dispose()", the crash does not happen.