Consolidate test utilities, harnesses and suites (#1)

libp2p/go-libp2p-transport#51

SubtestStress is exposed but it was not possible to build a working opt parameters.

pass contexts to OpenStream in tests

Defer closing stream for reading

Run `go mod tidy`

Resolve staticcheck issues:
- SA2002 `t.Fatal`  must be called in the same goroutine as the test
- U1000 unused struct
- ST1005 error string should not be capitalized

The `go vet` issues were the same as the ones reported by `saticcheck`.

Relates to:
- https://github.com/orgs/ipfs/projects/12#card-58209321

Address `go vet` and `saticcheck` issues

fix: cleanup transport suite

We don't close the connection before the echo hasn't returned, but echo won't
return before AcceptStream has returned an error, which only happens when the
connection is closed.

fix deadlock in the transport's serve function

add mocks for the resource manager

…2p/transport/testsuite