[Code] Use seq_no and primary_term to do ES concurrency control for EsQueue and reenable code tests

[mw-ding]

Summary

The reason for the recent Code test failures is that ES snapshot now explicitly throws the following errors if querying ES with version for concurrency control. The esqueue library lives inside code currently uses this stale way to do it. Updating to seq_no and primary_term fixes the problem.

{
   "msg":"[action_request_validation_exception] Validation Failed: 1: internal versioning ca
n not be used for optimistic concurrency control. Please use `if_seq_no` and `if_primary_t
erm` instead;",
   "path":"/.code_internal-worker-queue-2019-07-14/_update/jy7i3gf921vlaf57096
6lf05",
   "query":{
      "type":"_doc",
      "version":1
   },
   "body":"{\"doc\":{\"attempts\":1,\"started_at\":\"2019-07-17T17:25:20.920Z\",\"process_expiration\":\"2019-07-17T18:25:20.920Z\",\"status
\":\"processing\"}}",
   "statusCode":400,
   "response":"{\"error\":{\"root_cause\":[{\"type\":\"action_request_validation_exception\",\"reason\":\"Validation Failed: 1: internal versioni
ng can not be used for optimistic concurrency control. Please use `if_seq_no` and `if_primary_term` instead;\"}],\"type\":\"action_request_validation_exception\",\"reason\":\"Valid
ation Failed: 1: internal versioning can not be used for optimistic concurrency control. Please use `if_seq_no` and `if_primary_term` instead;\"},\"status\":400}"
}

Checklist

Use strikethroughs to remove checklist items you don't feel are applicable to this PR.

• This was checked for cross-browser compatibility, including a check against IE11
• Any text added follows EUI's writing guidelines, uses sentence case text and includes i18n support
• Documentation was added for features that require explanation or tutorials
• Unit or functional tests were updated or added to match the most common scenarios
• This was checked for keyboard-only and screenreader accessibility

For maintainers

• This was checked for breaking API changes and was labeled appropriately
• This includes a feature addition or change that requires a release note and was labeled appropriately

[elasticmachine]

Pinging @elastic/code

[elasticmachine]

💔 Build Failed

• continuous-integration/kibana-ci/pull-request

[mw-ding]

Confirmed that this change on ES's end has been merged these 2 days.

A more formal discussion on this can be found here: elastic/elasticsearch#38254

[elasticmachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request