Insert a C label for associated with an escapemark

Property definitions

nitc $ AbstractCompilerVisitor :: add_escape_label
	# Insert a C label for associated with an escapemark
	fun add_escape_label(e: nullable EscapeMark)
	do
		if e == null then return
		if e.escapes.is_empty then return
		add("BREAK_{escapemark_name(e)}: (void)0;")
	end
src/compiler/abstract_compiler.nit:1598,2--1604,4