Prevent forward declaration in type parameters

Prevent forward declaration in type parameters

gcc/rust/ChangeLog:

	* resolve/rust-default-resolver.cc (DefaultResolver::visit): Add visit
	function for TypeParam.
	* resolve/rust-default-resolver.h: Add function prototype.
	* resolve/rust-forever-stack.h: Add function to check for forward
	declaration ban.
	* resolve/rust-late-name-resolver-2.0.cc (Late::visit): Check forward
	declarations.

Signed-off-by: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>