Fix isStandardSyntaxTypeSelector.test.js that use callbacks

[ybiquitous]

Which issue, if any, is this issue related to?

This is a part of #4881.

Is there anything in the PR that needs further explanation?

I disable some test cases due to failure as follows:

● isStandardSyntaxTypeSelector › shadow-piercing descendant combinator

  TypeError: Cannot read property 'parent' of undefined

    14 | 	// The fake-tag's "parent" is actually a selector node, whose parent
    15 | 	// should be the :nth-child pseudo node.
  > 16 | 	if (!node.parent || !node.parent.parent) {
       | 	          ^
    17 | 		return false;
    18 | 	}
    19 |

    at isStandardSyntaxTypeSelector (lib/utils/isStandardSyntaxTypeSelector.js:16:12)
    at Object.<anonymous> (lib/utils/__tests__/isStandardSyntaxTypeSelector.test.js:49:10)

The cause seems due to postcss-selector-parser has not supported Reference Combinator, but I don't know the details. 🤷
(maybe #2508 related?)

[ybiquitous]

Not covered by the test:

stylelint/lib/utils/isStandardSyntaxTypeSelector.js

Lines 47 to 50 in 6ad94ac

	// Reference combinators like `/deep/`
	if (node.value.startsWith('/') && node.value.endsWith('/')) {
	return false;
	}

https://coveralls.io/builds/34214757/source?filename=lib/utils/isStandardSyntaxTypeSelector.js#L49

[jeddy3]

LGTM, thanks!

Let's pick up the missing coverage and funkiness around reference combinators in other pull requests.