Use the new feature of Go 1.24, fix linter warnings.
This change was produced by:
- running golangci-lint run --fix
- sed 's/context.Background/t.Context/' -i `git grep -l context.Background | grep test.go`
- manually fixing broken tests
- itest, lntest: use ht.Context() where ht or hn is available
- in HarnessNode.Stop() we keep using context.Background(), because it is
called from a cleanup handler in which t.Context() is canceled already.
We want `context.TODO()` to be high signal in the code-base. It should
signal clearly that work is required to thread parent context through to
the call-site. So to keep the signal-to-noise ratio high, we remove any
context.TODO() calls from tests since these will never need to be
replace by a parent context.
After this commit, there is only a single context.TODO() left in the
code-base.
With go 1.17 a change to the build flags was implemented:
https://go.googlesource.com/proposal/+/master/design/draft-gobuild.md
The formatter now automatically adds the forward-compatible build tag
format and the linter checks for them, so we need to include them in our
code.
