Simplify issue lists in event test suite

[happy5214]

The expected issue lists in the event.spec.js test suite contain some redundant code, namely repeated calls to generateIssue and converterGenerateIssue. In the future, we should consider whether it would be desirable to condense these lists to include just the data and move those calls to the validator base functions.

For example, the current test in dataset.spec.js (a good example of one with multiple issue types), edited to the form of event.spec.js, would be:

[
  generateIssue('extension', {
    tag: testDatasets.multipleInvalid[0],
  }),
  generateIssue('unitClassInvalidUnit', {
    tag: testDatasets.multipleInvalid[1],
    unitClassUnits: legalTimeUnits.sort().join(','),
  }),
  converterGenerateIssue(
    'invalidTag',
    testDatasets.multipleInvalid[2],
    {},
    [0, 12],
  ),
]

Several possibilities exist for condensing this. Some are listed below.

{
  extension: [{
    tag: testDatasets.multipleInvalid[0],
  }],
  unitClassInvalidUnit: [{
    tag: testDatasets.multipleInvalid[1],
    unitClassUnits: legalTimeUnits.sort().join(','),
  }],
  invalidTag: [[
    testDatasets.multipleInvalid[2],
    {},
    [0, 12],
  ]],
}