Size utility functions, such as `hypertable_size()`, excluded
non-responding data nodes from size calculations, which led to the
functions succeeding but returning the wrong size information. To
avoid reporting confusing numbers, it is better to fail.
This change updates the SQL queries for the relevant functions to no
longer exclude non-responding data nodes and also adds a TAP test to
illustrate the error when data nodes are not responding.
Fixes#3713