Left nav scroll browser testing

[pollardld]

• [x] test for short screens
• [x] test section focus affect on sidebar scroll
• [x] scrollbar visibility on windows chrome (and others)
• [x] left hand overflow

[pollardld]

Tested on:

• Windows 10 Chrome 74
• Windows 10 Chrome 73
• Windows 10 Edge 17
• Windows 10 IE 11
• Windows 10 FF 66
• Windows 8.1 IE 11
• Windows 8 IE 10
• Mac OSx 10.4 Chrome 77
• Mac OSx 10.4 FF 66
• Mac OSx 10.4 Safari 12
• Mac OSx 10.3 Safari 11
• Mac OSx 10.3 Chrome 73

Screenshots (Some screen shots have the leftnav missing, these browsers were confirmed working by using realtime testing): https://links.lambdatest.com/XKPMI45FPDSOSGI6MHEKCTY2NNEQQ9H4F8YS65YN36CUOFKSIWOX9B6M1ANKYQL0