Adjust cross-version upgrade tests for seg_out() fix

Adjust cross-version upgrade tests for seg_out() fix

Commit 0e1f1ed157e taught seg_out() to print the certainty indicator
on an interval's upper boundary, but it was back-patched only as far
as v14.  When upgrading from an older release, the old server prints
the one test_seg row exercising that case ('4.6 .. ~7.0') without the
indicator, so the pre- and post-upgrade dumps do not match.  Make
AdjustUpgrade.pm delete just that row; seg's comparison function does
distinguish the certainty indicators, so the otherwise identical row
'4.6 .. 7.0' is unaffected.

Back-patch to all supported branches.

Per buildfarm members crake and fairywren.

Discussion: https://postgr.es/m/5ccbdbde-6467-4a10-bf4d-0be73a05ce8d@dunslane.net