e40x/s - Lump assert files together

[silabs-robin]

From discussion in https://github.com/openhwgroup/core-v-verif/pull/1399#discussion_r962960940

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We have many assertion files and they are all just dumped into the tb/uvmt/ directory. Let's create tb/asserts/ or something similar and have the files more cleanly organized that way. (The inference is "lumped > dumped")

Additionally, remove the core/ stuff from the uvmt ".flist" file.

Consider also, whether we might want a separate ".flist" file for the assertion files (to help share code between sim/fv).

[silabs-robin]

(The inference is "lumped > dumped")

[MikeOpenHWGroup]

Thanks for creating this issue @silabs-robin. I think it will be of interest to the E40P team as well (@pascalgouedo, @YoannPruvost). I like the idea of moving all assertion files from <core>/tb/uvmt/uvmt_<core>_*_assert.sv to <core>/tb/assert/<core>_*_assert.sv.

Having a separate manifest (flist) is also a good idea. Hopefully we can create a unified one that can be used for both simulation and formal verification.

The <core>/tb/assert directory should also have a README listing the purpose of each file and which FV tool(s) have been used with the assertions.

[silabs-mateilga]

The interfaces in uvmt_[core]_tb_ifs.sv should also be placed in one file per interface, and organised in a directory, as for asserts.

[silabs-robin]

Status: I have moved files over as I have worked on them https://github.com/openhwgroup/core-v-verif/tree/cv32e40s/dev/cv32e40s/tb/assertions .

(But, as I have not worked on all files, not all of them have been moved over.)