lt_tupcount - number of tuples in struct leftist *Tuples
	lasttuple   - last tuple put to disk by createfirstrun()

2. Limit number of tuples in leftist trees:
	- put one tuple from current tree to disk if limit reached;
	- end run creation if limit reached by nextrun.
3. Avoid mergeruns() if first run is single one!

	(default value for max number of tuples in leftist tree)

(-S memory,tuples)

 including DROP COLUMN, SET CONSTRAINT, etc.

 after adding separate sections for DEFAULT and CHECK.

Use conventions common to other regression test input files.
Leave non-temporary files at end of test.

 Still uses time_t declarations, but most code will be changed for next release.