go: Fix things staticcheck complains about

Client: go

Staticcheck is the recommended replacement of the frozen and deprecated
official golint linter [1].

Fix the things it complained about (or add lint:ignore directive) in:

- lib/go/thrift
- lib/go/test/tests
- tutorial/go/src
- test/go/src
- compiler generated code

The majority of the fixes are in the following categories:

- Use of deprecated function (mainly the TConfiguration related ones)
- Redundant break in switch cases
- Unused and unexported variables/fields/functions

Also in the same spirit as fb539ae, remove the error return from
NewTSSLSocket as it can never be non-nil.

This change will be cherry-picked into 0.15.0 branch after merged.

[1]: https://groups.google.com/g/golang-nuts/c/rCP70Aq_tBc