Factorize loop forward analysis.

Property definitions

nitc $ ADoBlockHelper :: accept_loop_forward_analysis
	# Factorize loop forward analysis.
	fun accept_loop_forward_analysis(v: StaticAnalysis) do
		var n_block = loop_block
		if not n_block == null then loop_fix_point(v, n_block)
	end
src/saf/saf_base.nit:190,2--194,4