pgsql: Add test case for when subscriber table is missing a column

Add test case for when subscriber table is missing a column

We haven't had bugs in this area, but there's some not-entirely
trivial code to detect that case, so it seems good to have test
coverage for it.

Author: Peter Smith <smithpb2250@gmail.com>
Reviewed-by: vignesh C <vignesh21@gmail.com>
Reviewed-by: Tomas Vondra <tomas@vondra.me>
Discussion:
https://www.postgresql.org/message-id/CAHut%2BPtX8P0EGhsk9p%3DhQGUHrzxeCSzANXSMKOvYiLX-EjdyNw@mail.gmail.com

Branch
------
master

Details
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https://git.postgresql.org/pg/commitdiff/19c6eb06c51f4da70e2ea0f1bdb64a0142e8e2aa

Modified Files
--------------
src/test/subscription/t/008_diff_schema.pl | 15 +++++++++++++++
1 file changed, 15 insertions(+)