ast: Infer static lifetime for const and static items

ast: Infer static lifetime for const and static items

(probably incomplete propagation)

gcc/rust/ChangeLog:

	* hir/rust-ast-lower-base.cc (ASTLoweringBase::lower_lifetime): Propagate static
	requirement.
	* hir/rust-ast-lower-base.h: Propagate static requirement.
	* hir/rust-ast-lower-implitem.h: Propagate static requirement.
	* hir/rust-ast-lower-item.cc (ASTLoweringItem::visit): Propagate static requirement.
	* hir/rust-ast-lower-type.cc (ASTLoweringType::translate): Propagate static requirement.
	(ASTLoweringType::visit): Propagate static requirement.
	* hir/rust-ast-lower-type.h: Propagate static requirement.

Signed-off-by: Jakub Dupak <dev@jakubdupak.com>