Remove -w (--ignore-all-space) option from pg_regress's diff calls.

We have used -w for a long time as a means of reducing the reported diff
volume when one element of a result table isn't of the expected width.
However, most of the time the results just pass anyway, so this isn't as
important as it once was.  Meanwhile, the risk of missing potentially
significant deviations has gone up, particularly with psql's ability to
report error cursor positions.  So, let's switch over to space-sensitive
comparisons.  Per my proposal of yesterday.

(All the expected files that I can test here seem to be ready for this
already, but we'll see what the buildfarm thinks about others.)

src/test/regress/pg_regress.c

@@ -11,7 +11,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/test/regress/pg_regress.c,v 1.65 2009/11/14 15:39:36 mha Exp $
+ * $PostgreSQL: pgsql/src/test/regress/pg_regress.c,v 1.66 2009/11/22 17:54:23 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -66,8 +66,8 @@ static char *shellprog = SHELLPROG;
 #endif
 
 /* currently we can use the same diff switches on all platforms */
-const char *basic_diff_opts = "-w";
-const char *pretty_diff_opts = "-w -C3";
+const char *basic_diff_opts = "";
+const char *pretty_diff_opts = "-C3";
 
 /* options settable from command line */
 _stringlist *dblist = NULL;