pgsql: Tweak the backend scanner (and psqlscan.l, which must track the

Log Message:
-----------
Tweak the backend scanner (and psqlscan.l, which must track the backend
scanner anyway) to avoid having any backup states. According to the
flex manual, this should speed things up, and indeed the backend scanner
is about a third faster according to some quick profiling checks.
I haven't tried to measure the speed change in psql, but it probably
is similar.

Modified Files:
--------------
pgsql/src/backend/parser:
scan.l (r1.121 -> r1.122)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/scan.l.diff?r1=1.121&r2=1.122)
pgsql/src/bin/psql:
psqlscan.l (r1.9 -> r1.10)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/psql/psqlscan.l.diff?r1=1.9&r2=1.10)