Stabilize just-added regression test cases.
The tests added by commits
029dea882 et al turn out to produce
different output under -DRANDOMIZE_ALLOCATED_MEMORY. This is
not a bug exactly: that flag causes coerce_type() to invoke
the input function twice when coercing an unknown-type literal
to a specific type. So you get tsqueryin's bleat about an empty
tsquery twice. Revise the test query to avoid that.
Discussion: https://postgr.es/m/
20230406213813.uep7plg6lvcywujo@awork3.anarazel.de