Test output of go tests is not printed in CI

[jsoriano]

When a go test fails, its output is not printed, difficulting the investigation of the problem.

For example the stacktrace of the failure in this build is only displayed as:

logger_test.go:43: 
    logger_test.go:59:

The problem may be in the library we use to parse the output to generate the junit files:

beats/dev-tools/mage/gotest.go

Line 255 in df03add

report, err := parser.Parse(bytes.NewBuffer(bufferOutput.Bytes()), BeatName)

Perhaps a different approach could be to do the parsing based on the JSON output of go test.

Ideally we should be able to:

• Always show the output of go test or equivalent information.
• Enable verbose output of go test when verbosity is enabled in mage.
• Still generate the junit files for jenkins.

[v1v]

Another example:

[jsoriano]

Maybe we can use gotestsum to fix this as explored here: #22541 Thanks @urso!