RISC-V: Benchmark with folder inputs

What

For the benchmark run command, arguments to --input will be expanded if the path is a folder to the immediate files inside that folder.

It also adds a warning message for when a binary has one iteration which does not complete with OK status.

Why

Expands usability of the microbenchmark component.

How

For every path given to --input <INPUTS> the program checks if it is a directory. If it is, then loop through the contents of that directory and take all the files and add them to the input list, but do not recursively check for directories. If not, just keep the file in the list.

Manually testing the MR

cd src/risc_v && make risc-v-sandbox

./risc-v-sandbox bench run --input ../../tezt/tests/riscv-tests/generated --mode simple --pretty --iter 2 --output uivcombined.json

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR