Icarus-verilog v11

[quark17]

Homebrew now provides icarus-verilog v11, so that's the version that the macOS CI installs. This results in a mismatch in bsc.options when testing an imported-C example for Verilog -- the exepected sysGCD.bsc-vcomp-out has this additional line:

SFT files are deprecated. Please pass the VPI module instead.

I suspect that the bsc_build_vsim_iverilog script in BSC will need to be updated to check the iverilog version and to use different VPI arguments when the version is 11. But we could also resolve it in the testsuite -- there's currently code in the options.exp file that ignores certain iverilog warnings, so it could be made to ignore that warning, too.

There are also a number of places in the testsuite where we expect verilog tests to fail, for certain versions of iverilog, due to bugs in the VPI support. It would be good to check to whether any of these bugs have been fixed and can be enabled when the iverilog version is 11.