JTAG: Use sorted map for stability (#1073)

* JTAG: Use sorted map for stability

Otherwise the generated FIRRTL/Verilog is non deterministic

* jtag : parens for clarity

* jtag: Use deterministic ListMap and sort for stability

* JTAG: use slightly clearer SortedMap (clearer to me anyway)

* jtag: whitespace cleanup