Add semicolons to eval'd strings to hide a minor Perl behavioral change.

"eval q{foo}" used to complain that the error was on line 2 of the eval'd
string, because eval internally tacked on "\n;" so that the end of the
erroneous command was indeed on line 2.  But as of Perl 5.18 it more
sanely says that the error is on line 1.  To avoid Perl-version-dependent
regression test results, use "eval q{foo;}" instead in the two places
where this matters.  Per buildfarm.

Since people might try to use newer Perl versions with older PG releases,
back-patch as far as 9.0 where these test cases were added.

src/pl/plperl/sql/plperl_init.sql

@@ -3,7 +3,7 @@
 -- Avoid need for custom_variable_classes = 'plperl'
 LOAD 'plperl';
 
-SET SESSION plperl.on_plperl_init = ' system("/nonesuch") ';
+SET SESSION plperl.on_plperl_init = ' system("/nonesuch"); ';
 
 SHOW plperl.on_plperl_init;