Save draft icon disappears on screens between 600 & 800px wide.

[peterwilsoncc]

Describe the bug
On screens with a width of between 600 and 800px, the save draft icon does not display within the button. Hovering and clicking the button still work but a user needs to know it is there.

I've taken the liberty of labelling this as high priority as it relates to the saving and publishing workflow. Feel free to modify that if I've misunderstood the labelling system/you disagree.

To reproduce
Steps to reproduce the behavior:

1. Go to the block editor edit screen
2. Reduce the browser width to 700px
3. Observe neither the save draft text or icon is visible.
4. Hover and click where you would expect the icon to be visible, you will see the hover state.

Expected behavior
At those widths, it looks like displaying the icon in the intended behavior.

Screenshots

Desktop (please complete the following information):

• OS: macOS 10.13.6
• Browser: Chrome 76
• Gutenberg version: Tested 6.3 and 6.4 (gif from 6.3)