If attrs is an array_ref, open the target array and return its shape-
derived metadata. Returns null when no resolution is needed (caller
should keep the original array/attrs). Un-memoised and unwrapped — prefer a
RefTargetMemo (what RangeLoader.loadRangesResolvingRef uses).
If
attrsis an array_ref, open the target array and return its shape- derived metadata. Returnsnullwhen no resolution is needed (caller should keep the original array/attrs). Un-memoised and unwrapped — prefer a RefTargetMemo (whatRangeLoader.loadRangesResolvingRefuses).