Add tests for websocket connection errors

[cgewecke]

Description

These are the same tests proposed for #3190 but aimed at 1.x. They show that the current 1.x behavior when connecting to a non-existent url is to fire an error with this message

connection not open on send

[coveralls]

Coverage increased (+0.2%) to 85.141% when pulling 08dac48 on test/websocket-err-baseline into 9b4b68a on 1.x.

[nivida]

@cgewecke Thanks for creating this! I'm wondering why the requirement now is to have this error message in PR #3190 and why you were arguing to not have it in PR #3171.

[cgewecke]

@nivida RE: #3171 could you explain further? I've just checked and the only thing I see is a discussion about whether it's safe to remove the console.error('connection not open on send()').

[cgewecke]

This was discussed at the web3 meeting and is close-able.