[CTG] Add cli param env_dir

[trdthg]

Description

#529 I think that a fixed env_dir either ./ or ~/riscv-arch-test/riscv-test-suite/env is not suitable for everyone anyway.

Why not set it as a new cli param?

I personally prefer to place riscv-arch-test in the current directory(test_dir) via a symbolic link, which would be ./riscv-arch-test/riscv-test-suite/env. Considering our different for the default path, I just casually wrote a ./ here.

[UmerShahidengr]

This will change the script to run CTG, all scripts will now require a new command line parameter otherwise existing scripts will stop working, I don't recommend such changes which will affect all users without proper discussion and documentation. This will require changes in the documentation and announcement for everyone that a new CLI parameter has been added.

[trdthg]

what about keep the default value to ~/riscv-arch-test/riscv-test-suite/env
At least all scripts do not need to be modified

[trdthg]

keep the default value to ~/riscv-arch-test/riscv-test-suite/env

done