Dereference after null check

Either the check against null is unnecessary, or there may be a null pointer dereference. Pointer is checked against null but then dereferenced anyway
/src/mongo/db/exec/sbe/stages/hashagg_base.cpp:251: FORWARD_NULL 177448 Calling "this->_recordStore.operator bool()" implies that "this->_recordStore" might be null-like.