Re: WIP Incremental JSON Parser

Coverity complained that this patch leaks memory:

/srv/coverity/git/pgsql-git/postgresql/src/bin/pg_combinebackup/load_manifest.c: 212 in load_backup_manifest()
206     			bytes_left -= rc;
207     			json_parse_manifest_incremental_chunk(
208     												  inc_state, buffer, rc, bytes_left == 0);
209     		}
210     
211     		close(fd);
>>>     CID 1596259:    (RESOURCE_LEAK)
>>>     Variable "inc_state" going out of scope leaks the storage it points to.
212     	}
213     
214     	/* All done. */
215     	pfree(buffer);
216     	return result;
217     }

/srv/coverity/git/pgsql-git/postgresql/src/bin/pg_verifybackup/pg_verifybackup.c: 488 in parse_manifest_file()
482     			bytes_left -= rc;
483     			json_parse_manifest_incremental_chunk(
484     												  inc_state, buffer, rc, bytes_left == 0);
485     		}
486     
487     		close(fd);
>>>     CID 1596257:    (RESOURCE_LEAK)
>>>     Variable "inc_state" going out of scope leaks the storage it points to.
488     	}
489     
490     	/* Done with the buffer. */
491     	pfree(buffer);
492     
493     	return result;

It's right about that AFAICS, and not only is the "inc_state" itself
leaked but so is its assorted infrastructure.  Perhaps we don't care
too much about that in the existing applications, but ISTM that
isn't going to be a tenable assumption across the board.  Shouldn't
there be a "json_parse_manifest_incremental_shutdown()" or the like
to deallocate all the storage allocated by the parser?

			regards, tom lane