[CI] 3 hour timeout is not enough

[Disasm]

There was only one successful build in the last 24 hours: #58446 (comment)
All other builds were failed with timeout either on Travis or AppVeyor.

Related: #58160

[pietroalbini]

The infra team already discussed this in the past, and our consensus is to keep the timeout to 3 hours. Our CI builds already take too long, limiting the amount of PRs we can merge in a day even if each of them doesn't fail. We prefer to work torwards reducing the amount of time spent on CI, and the timeout is an incentive to do so.