This patch intoduces a coverage model and the generated
test cases using riscv_ctg.

The tests have been generated using the following command:
  riscv_ctg.py \
    --cgf coverage/dataset.cgf \
    --cgf coverage/zicond.cgf \
    -bi rv32i \
    -d tests/
  riscv_ctg.py \
    --cgf coverage/dataset.cgf \
    --cgf coverage/zicond.cgf \
    -bi rv64i \
    -d tests64/

The resulting tests have been copied to the target directory:
  cp tests/*S riscv-test-suite/rv32i_m/Zicond/src/
  cp tests64/*S riscv-test-suite/rv64i_m/Zicond/src/

This PR depends on Zicond support in the riscv-ctg repo:
  riscv-software-src/riscv-ctg#59

Signed-off-by: Christoph Müllner <[email protected]>

Signed-off-by: Allen Baum <[email protected]>