Environment
Provide version numbers for the following components (information can be retrieved by running tns info in your project folder or by inspecting the package.json of the project):

• CLI: 6.0.0
• Cross-platform modules: 6.0.2
• Android Runtime: 6.0.0
• iOS Runtime: 6.0.0
• Plugin(s):

Describe the bug
Dynamically generating tabs that have an icon source set to a font crashes the app under android. Under iOS make the tabs not visible similar to #7609

To Reproduce
https://play.nativescript.org/?template=play-tsc&id=pqj9gl&v=2
Tap on the Change button

Expected behavior
To work 😀

Related to #6967