Instruct Coverity using an assertion.
Instruct Coverity using an assertion.

This should make Coverity deduce that plperl_call_perl_func() does not
dereference NULL argtypes.  Back-patch to 9.5, where the affected code
was introduced.

Michael Paquier

zeroae/postgres-xl,zeroae/postgres-xl,zeroae/postgres-xl,zeroae/postgres-xl,zeroae/postgres-xl