[test] Versions of Verilator >= 5.0 require --timing or --no-timing options for top level sim builds

### Description

While running the getting started tests recently I found myself coming up against Verilator build issues - it turns out that from version 5 onwards verilator requires either a --timing or a --no-timing option to be passed when it finds timing delays in any files.

The vio_pgd.sv & vcc_pgd.sv files contain some delays so it won't build the sim.

There are a few options to fix but I think the only backwards compatible option is to wrap up the delays in `/*verilator timing_off*/` & `/*verilator timing_on*/` meta comments - I can put together a PR for this if there is interest in supporting higher versions of verilator?

Start with vio_pgd.sv and vcc_pgd.sv, then reproduce the failure through the getting started tests using Verilator 5 or newer. Check the simulator build's handling of the timing delays and verify that the affected top-level simulation builds successfully while remaining compatible with older Verilator versions.

Written by the indexing model from the issue text.