Path::Tiny is not in core, but it has no non-core dependencies, so is a very quick and easy installation.
use Path::Tiny qw(path);
path("/usr/bin")->subsumes("/usr/bin/perl"); # true
Now, it does this entirely by looking at the file paths (after canonicalizing them), so it may or may not be adequate depending on what sort of behaviour you're expecting in edge cases like symlinks. But for most purposes it should be sufficient. (If you want to take into account hard links, the only way is to search through the entire directory structure and compare inode numbers.)