Fix visual progress formatting for HAR file
Fix visual progress formatting for HAR file

A recent change to visual progress json formatting modified the
structure of visual progress data in HAR files, which led to visual
progress data being displayed incorrect in compare.sitespeed.io.

This commit changes the visual progress data structure back into what is
expected in HAR files.

sitespeedio/browsertime,sitespeedio/browsertime,tobli/browsertime,sitespeedio/browsertime,sitespeedio/browsertime