Review backends group

- write_intersynth;
- write_json;
- write_simplec;
- write_smt2;
- write_smv;
- write_spice;
- write_table;
- write_verilog;
- write_xaiger.

- write_aiger;
- write_blif;
- write_btor;
- write_edif;
- write_firrtl;
- write_ilang.

Review and update tests in 'architecture' test group

The third variant of changes in yosys-tests

Fix failed tests for ice40_wrapcarry; Add tests for new options.

- Fix abc_model.v to abc9_model.v in techlibs paths;
- synth_xilinx. Add tests for new options;
- synth_ecp5. Add tests for new options;
- Expand coverage for synth_dsp command;

Fix regressions on build #177 and #179;