Steps to reproduce:
1. Open the attached project (vrSupport.zip)
2 Check Editor settings, notice that "Virtual Reality Supported" is enabled
3. Go to Build Settings, switch platform to WebGL
4. From menu choose Oculus platform > Enable (Will execute PlayerSettings.virtualRealitySupported = true)
5. Save the scene
6. Go to Build Settings and click Build
7. Observe the crash at VREditorModule::GetStereoDeviceEnabled

Expected result: Building without problems
Actual result: Unity crashes

Reproduced with: 5.4.2p2, 5.4.2p3, 5.5.0b7, 5.5.0b11
Not reproduced with: 5.3.6p4, 5.4.1f1,, 5.5.0b5, 5.5.0b6
Regression introduced in 5.4.2p2