Verifies that CSS.fontsUpdated events contain additional information for variable fonts
Variation axes of the Sixtyfour font (can be verified using Python fontTools or wakamaifondue.com):
[
    [0] : {
        defaultValue : 200
        maxValue : 900
        minValue : 200
        name : Weight
        tag : wght
    }
    [1] : {
        defaultValue : 100
        maxValue : 200
        minValue : 100
        name : Width
        tag : wdth
    }
]