d: Improve TypeInfo errors when compiling in -fno-rtti mode

d: Improve TypeInfo errors when compiling in -fno-rtti mode

The existing TypeInfo errors can be cryptic.  This alters the diagnostic
to include which expression is requiring `object.TypeInfo'.

gcc/d/ChangeLog:

	* d-tree.h (check_typeinfo_type): Add Expression* parameter.
	(build_typeinfo): Likewise.  Declare new override.
	* expr.cc (ExprVisitor): Call build_typeinfo with Expression*.
	* typeinfo.cc (check_typeinfo_type): Include expression in the
	diagnostic message.
	(build_typeinfo): New override.

gcc/testsuite/ChangeLog:

	* gdc.dg/rtti1.d: New test.