Check for stack overflow when rewriting graph queries

Check for stack overflow when rewriting graph queries

generate_queries_for_path_pattern_recurse() and
generate_setop_from_pathqueries() are recursive functions.  For a
property graph with hundreds of tables, a graph pattern with a handful
element patterns can cause stack overflow.  Fix it by calling
check_stack_depth() at the beginning of these functions.

Author: Satyanarayana Narlapuram <satyanarlapuram@gmail.com>
Reviewed-by: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Discussion: https://www.postgresql.org/message-id/CAHg+QDfgK0xddH8f3eAb+UVn7sBDOnv8RvM6OkP4HtHAt6aD7w@mail.gmail.com