Test program paths are hardcoded

[lmbollen]

The paths in clash-vexriscv-sim/tests/tests.hs are hardcoded relative to the project root.
This causes cabal run unittests tot fail for clash-vexriscv-sim when you are in the package directory.

We should rewrite this to either:

• Dynamically find the project root use that as base path for the relative paths.
• Move the files to the data-files segment of the package and use getDataFileName from the implicit Paths_clash_vexriscv_sim module.

Example: https://github.com/clash-lang/clash-vexriscv/blob/main/clash-vexriscv-sim/tests/Tests/Jtag.hs#L24-L52