How to reproduce:
1. Open the attached UnityBug_OpenGLES2Removed.zip
2. Build for iOS and open the Xcode project
3. Modify the Info.plist file: remove "metal" from "Required device capabilities"
4. Deploy the Xcode project to the iOS device

Reproducible with: 2019.3.0a2, 2019.3.5f1

Reproducible with:
- iPad 4th generation (10.3.3)

Notes:
- Could not find another device which does not support metal
- OpenGLES was deprecated in 2019.3 so could not test with earlier versions
- OpenGLES is deprecated, but the app should still not crash. Looks like OpenGLES was removed and must be added manually

The workaround would be to add manually OpenGLES to Graphics API

First lines of a stack trace:
frame #0: 0x1d555acc libsystem_kernel.dylib`__pthread_kill + 8
frame #1: 0x1d60e086 libsystem_pthread.dylib`pthread_kill + 62
frame #2: 0x1d4ea95a libsystem_c.dylib`abort + 108
frame #3: 0x1cfef708 libc++abi.dylib`abort_message + 108
frame #4: 0x1d006552 libc++abi.dylib`default_terminate_handler() + 270
frame #5: 0x1d00f31e libobjc.A.dylib`_objc_terminate() + 234