wget returns exit code 8

[nipunn1313]

We end up seeing this occasionally.

My guess is that wget from github occasionally fails. Most likely one or two retries inside the setup-mold step would go a long way here. Other suggestions welcome too.

[nipunn1313]

wget claims to handle retries for faulty network effectively, but yet we're still seeing this occasionally. Without additional logging, it's hard to tell what's going on.

[rui314]

I saw this before too. wget should retry up to 20 times, but I'm not sure if it works with -O (redirecting output to the standard output). Let's use curl instead.