NoOp err in v2 timeout not possible

[gjermundgaraba]

In channel v2 timeout the switch on err is using the err from a previous context because it is done as a if err := (i.e. it will always be nil and the noOp case can never happen).

Also, add tests for noOp scenarios across channel-04 v2 to make sure it works everywhere.

[iIvaki]

@gjermundgaraba can I do this?

[gjermundgaraba]

Thank you for your interest @iIvaki, but I think the core team will take this one.