libiberty: Add support for demangling D function literals as template value parameters

The D language now allows instantiating templates using struct literals
that have function literal fields as a value argument.

libiberty/ChangeLog:

	* d-demangle.c (dlang_parse_arrayliteral): Add 'info' parameter.
	(dlang_parse_assocarray): Likewise.
	(dlang_parse_structlit): Likewise.
	(dlang_value): Likewise.  Handle function literal symbols.
	(dlang_template_args): Pass 'info' to dlang_value.
	* testsuite/d-demangle-expected: Add new test.