pgsql: Avoid fetching past the end of the indoption array.

Avoid fetching past the end of the indoption array.

pg_get_indexdef_worker carelessly fetched indoption entries even for
non-key index columns that don't have one. 99.999% of the time this
would be harmless, since the code wouldn't examine the value ... but
some fine day this will be a fetch off the end of memory, resulting
in SIGSEGV.

Detected through valgrind testing. Odd that the buildfarm's valgrind
critters haven't noticed.

Branch
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REL_11_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/a7ca25cf787c563a92eef5eff1a8d2bb1364a992

Modified Files
--------------
src/backend/utils/adt/ruleutils.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)