Correctly assign a left and a right value

Boxing and unboxing is performed if required

Property definitions

nitc $ JavaCompilerVisitor :: assign
	# Correctly assign a left and a right value
	# Boxing and unboxing is performed if required
	fun assign(left, right: RuntimeVariable) do
		add("{left} = {autobox(right, left.mtype)};")
	end
src/compiler/java_compiler.nit:756,2--760,4