ParaView build from source Mac, hangs on file -> load

@utkarsh.ayachit @cory.quammen

I am still on MacOS 10.14.6, cmake options are enabling python (3.8) and Release instead of Debug. Qt version is 5.12.

Doing File -> Load, File -> Save, Load state all cause the gui to hang. It seems anything that opens a file browser causes a hang.

Steps to reproduce:

1. Build paraview from source (release branch)

• Enable python (3) and choose release instead of debug build

2. File -> load -> pinwheel and have to kill the process

Video (doesn't show the pinwheel, but it's there)