We were calling `expand_glob` on our excludes, which is very expensive
and unnecessary because we can pattern match while traversing instead.
1. Doesn't expand "exclude" globs. Instead pattern matches while walking
the directory.
2. Splits up the "include" into base paths and applicable file patterns.
This causes less pattern matching to occur because we're only pattern
matching on patterns that might match and not ones in completely
unrelated directories.
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