Dump all the hierarchy of BasicBlock from block to the leaves

Property definitions

nitc $ BlockDebug :: dump
	# Dump all the hierarchy of BasicBlock from `block` to the leaves
	fun dump(block: BasicBlock)
	do
		# Write the basic blocks hierarchy in output file
		file.write("digraph basic_blocks\n\{\n")
		var i = 0
		file.write(print_block(block, i))
		file.write("\n\}")

		file.close
	end
src/ssa.nit:527,2--537,4