Let simple array data in test.each() serve as automatic labels

[Krinkle]

Follows-up #1568

What are you trying to do?

Code that reproduces the problem:

QUnit.test.each( 'escapeRegExp [specials]', [
	'foo',
	'bar',
	'_',
	'+',
	'-',
	'^',
	'$'
], function ( assert, str ) {
	assert.propEqual(
		str.match( new RegExp( mw.util.escapeRegExp( str ) ) ),
		[ str ],
		'confirm correct escaping by being able to match itself'
	);
} );

What did you expect to happen?

For simple cases like this, it would be valuable I think if we can let values serve dual-purpose as the test name suffix. In other words as:

• mytest [foo]
• mytest [bar]
• mytest [_]

What actually happened?

• mytest [0]
• mytest [1]
• mytest [2].