[1.x,2.x] Respect errors in array cursors - TSM cleanup

[davidby-influx]

Errors in array cursors are ignored in many situations.

The function signatures for calls that are currently masking errors need to return those errors, and the errors need to be checked in calling functions.

• Ignoring errors here and here
• reset needs to return an error which is respected and passed back here
• Next does return an error, but it is always nil in the current code, regardless of underlying errors
• Unfortunately, the caller of arrayCursorIterator.Next also ignores any error returned by that function
• Instead, we should set c.err with the error.

This failure path is the root cause of this panic