Add code coverage and riscv-dv random tests

Created by: ASintzoff

• to support code coverage, test output files need to have a unique name (add timestamp to the filename)
• provide a way to exclude some modules from coverage (e.g. rvfi_tracer module)
• to support riscv-dv random tests, use unique name for program file to be loaded (no more Mem_init.txt)