Fixed split_maybe_args to split on default shell IFS (space, tab, ne…

[Sandijigs]

This PR fixes the split_maybe_args function in run-make-support to correctly split
on default shell IFS characters (space, tab, newline), instead of only splitting
on spaces.

Relates to implement shell whitespace splitting correctly

[rustbot]

The run-make-support library was changed

cc @jieyouxu

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[jieyouxu]

Thanks for the PR. However, I am going to close this PR in favor of an earlier PR (#154479) when the PR author already claimed the issue.

[jieyouxu]

Also, please do not submit PR descriptions generated via LLMs.

[Sandijigs]

Thanks for the PR. However, I am going to close this PR in favor of an earlier PR (#154479) when the PR author already claimed the issue.

oh , okay , I made this PR in reference to the outreachy issue :implement shell whitespace splitting correctly