Simulator collapse button in portrait mode shows two arrows

[jwunderl]

Describe the bug

in portrait mode, simulator collapse button has two arrows (downwards, and a darkened version of the landscape collapse arrow that goes away on hover

To Reproduce

Steps to reproduce the behavior:

1. Go to editor in thin browser window
2. see error in simulator collapse button

Expected behavior

shouldn't have second arrow

Screenshots

both ios and chrome

Desktop (please complete the following information):

• OS: mac
• Browser chrome

Smartphone (please complete the following information):

• Device: ios simulator

[ChaseMor]

Fixed in microsoft/pxt#5630