Special verilog parameters tb_path and output_path don't work in Riviera-PRO

[pib88]

When you use tb_path or output_path in verilog they are specified in command line like this: -gtb_path=<TB_PATH>

That does not work in Riviera because you need to put string in double quotes to have it interpreted correctly: -gtb_path="<TB_PATH>"

Since it's impossible to determine parameter type by its value, solution should be limited to parameters that we know are strings: tb_path and output_path.

[dalex78]

It look good to me, however, I do not have Riviera and cannot confirm the issue or the proposed fix. But I do not see any issue with the code. @LarsAsplund, I suggest to merge.