cobol: Sort table within a table.

Modify SORT to accept qualified names and nested table names. Mostly
changes lexer sort_state start condition to be more conservative with
what it recognizes.

gcc/cobol/ChangeLog:

	PR cobol/123890
	* Make-lang.in: Remove unneeded message suppression for scan.l.
	* parse.y: SORT uses tableish, not tableref.
	* scan.l: Use usual Procedure Division name recognition for SORT.