bug#39679: DuckDuckGo search results forgotten when GNU LibreJS is disabled

[Maxim Cournoyer]

Hello,

I've noticed that when using Icecat with LibreJS disabled, the DDG
search results are not "remembered" upon hitting Alt-LeftArrow or
clicking the back button, and instead a blank DuckDuckGo page is shown.

Steps to reproduce:

1. Go to settings, disable LibreJS
2. Use the URL/search bar to enter a search query
3. Click on one of the links returned on the DDG query page.
4. Hit back.
5. Notice the blank DDG page instead of the previous list of results.

Thanks for the great work on Icecat!

Maxim