Steps to repro:

1. Open Unity;
2. Open attached project;
3. In the Game view window expand 'Aspect ratio' dropdown list;
4. Click '+' button;
5. In the opened window type long value to both 'Width' and 'Height' fields (e.g. 99999x99999);
6. Click OK button.

Actual result:
Unity crashes (see attached gif video and screenshot).

Debug info from gdb (from Editor.log):

=================================================================
Got a SIGABRT while executing native code. This usually indicates
a fatal error in the mono runtime or one of the native libraries
used by your application.
=================================================================

Regression introduced in Unity 5.4.
This bug is apparently related to partial fix of this case: http://fogbugz.unity3d.com/default.asp?778272, but with different stacktrace and slightly different triggering conditions.

Expected result:
- Unity should not crash;
- Correct error message about clamped GameView size should be displayed (see attached expected.png file).

Notes:
- Reproducible in: 5.5.0a1, 5.4.0b20;
- Not reproducible in 5.3.5f1;
- Reproducible on both Windows 10 and OSX 10.11.4;
- Reproducible for toggling fields in 'Fixed Resolution' mode. Doesn't repro with 'Aspect Ratio' mode;
- Reproducible when overflowing both Height and Width fields. If overflowing only one of them, correct error message is displayed and Unity doesn't crash;
- Reproduces in both D3D11 and OpenGlCore modes.