gccrs: Make some general improvements

gccrs: Make some general improvements

gcc/rust/ChangeLog:

	* ast/rust-ast-visitor.cc (DefaultASTVisitor::visit): Visit the
	generic parameters of TraitItemType.
	* expand/rust-expand-visitor.h (is_derive): Remove defunct
	function declaration.
	* hir/rust-ast-lower-item.cc (ASTLoweringItem::visit): Remove
	unnecessary copy.
	* resolve/rust-name-resolver.cc (Resolver::Resolver): Skip
	generating builtins for the old resolver.
	* util/rust-hir-map.cc (Mappings::get_next_node_id): Detect node
	id exhaustion.
	* util/rust-mapping-common.h (MAX_NODEID): Add macro definition.

Signed-off-by: Owen Avery <powerboat9.gamer@gmail.com>