lint for tests with link rel=match and testharness.js

[gsnedders]

WebKit/WebKit#28071 showed up that we have a number of tests with both <script src=testharness.js> and <link rel=match>, which we should probably have a lint for.

wpt/tools/lint/lint.py

Lines 451 to 469 in c5ced76

	testharnessreport_nodes: List[ElementTree.Element] = []
	if source_file.testharness_nodes:
	test_type = source_file.manifest_items()[0]
	if test_type not in ("testharness", "manual"):
	errors.append(rules.TestharnessInOtherType.error(path, (test_type,)))
	if len(source_file.testharness_nodes) > 1:
	errors.append(rules.MultipleTestharness.error(path))
	testharnessreport_nodes = source_file.root.findall(".//{http://www.w3.org/1999/xhtml}script[@src='/resources/testharnessreport.js']")
	if not testharnessreport_nodes:
	errors.append(rules.MissingTestharnessReport.error(path))
	else:
	if len(testharnessreport_nodes) > 1:
	errors.append(rules.MultipleTestharnessReport.error(path))
	required_elements.extend(key for key, value in {"testharness": True,
	"testharnessreport": len(testharnessreport_nodes) > 0,
	"timeout": len(source_file.timeout_nodes) > 0}.items()
	if value)

looks like it might be intended to lint for this, but if the testharness test type wins out (which it does!) then you don't get a lint error in this case.