Mac-specific issue: There is an ability to add an uncompilable script to GO.

To repro:
1. Create a new project. Create a new GO.
2. In Project tab create a new C# script.
3. Open it (in MD) and add some error (like redundant "/"). Save script.
4. Navigate to Unity. In Project select the script and drag it to GameObject in Hierarchy.

Actual result: Script is added to GameObject.

Expected result: User gets an error: "Please fix compile errors before creating new script components" and script is not added to GameObject.

Regression introduced in OSX Unity 5.5.0b5.
Works fine in OSX Unity 5.5.0b4 (9f8737ccd563).

In Windows Unity 5.5.0b5 user gets error: "Please fix compile errors before creating new script components"