pgsql: Reset context at the tail end of JITed EEOP_AGG_PLAIN_TRANS.

Reset context at the tail end of JITed EEOP_AGG_PLAIN_TRANS.

While no negative consequences are currently known, it's clearly wrong
to not reset the context in one of the branches.

Reported-By: Dmitry Dolgov
Author: Dmitry Dolgov
Discussion: https://postgr.es/m/CAGPqQf165-=+Drw3Voim7M5EjHT1zwPF9BQRjLFQzCzYnNZEiQ@mail.gmail.com
Backpatch: 11-, where JIT compilation support was added

Branch
------
REL_11_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/0171ad9308ac232d5934d548a2adc898b794c5e0

Modified Files
--------------
src/backend/jit/llvm/llvmjit_expr.c | 2 ++
1 file changed, 2 insertions(+)