Enhance sqlite3_shutdown() so that it automatically invokes

sqlite3_reset_auto_extension().  This is a harmless no-op if applications
are already calling sqlite3_reset_auto_extension() prior to sqlite3_shutdown().
And it prevents possible memory corruption if they do not.  So it works
either way.  Most of the changes are to the test cases. (CVS 6475)

FossilOrigin-Name: 0c41f7cff4f6ffb9321f6f6b6ef3e431b750d41a

test/speed1.test

@@ -11,7 +11,7 @@
 # This file implements regression tests for SQLite library.  The
 # focus of this script is measuring executing speed.
 #
-# $Id: speed1.test,v 1.10 2008/10/15 11:43:55 danielk1977 Exp $
+# $Id: speed1.test,v 1.11 2009/04/09 01:23:49 drh Exp $
 #
 
 sqlite3_shutdown
@@ -293,4 +293,6 @@ speed_trial_summary speed1
 db close
 sqlite3_shutdown
 eval sqlite3_config_lookaside $old_lookaside
+sqlite3_initialize
+autoinstall_test_functions
 finish_test