Fix parsing problem with array initialisers

Fix parsing problem with array initialisers

The D parser has to cope with two types of array:

	int foo = 10
	new byte[foo]

and:

	alias char[] foo
	new byte[foo]

When it parses the new line, it's not ready to resolve the symbol foo, so it
assumes the second case and then rewrites it later during the semantic pass if
foo turns out to be an expression instead. Turning foo into foo? broke that.