Fix tests on 5.22 and 5.24

Data::Checks also needs to export `experimental 'lexical_subs'` for
`perl`s before 5.26.

Also one test needs to have `experimental 'postderef'` for
`perl`s before 5.24.

Author: zmughal

lib/Data/Checks.pm

@@ -18,7 +18,7 @@ sub import {
     strict->import::into($caller);
     warnings->import::into($caller);
     feature->import::into( $caller, ':5.22' );
-    experimental->import::into( $caller, 'signatures' );
+    experimental->import::into( $caller, 'signatures', 'lexical_subs' );
     Data::Checks::Parser->import::into( $caller, @args );
 }
 
@@ -86,7 +86,7 @@ The statement C<use Data::Checks> is equivalent to:
     use strict;
     use warnings;
     use v5.22;
-    use experimental 'signatures';
+    use experimental 'signatures', 'lexical_subs';
     use Data::Checks::Parser;    # this is the magic
 
 =head1 CORE CHECKS

t/bug-state-error.t

@@ -2,6 +2,7 @@
 
 use Test::Most;
 use Data::Checks;
+use experimental qw(postderef);
 
 explain <<'END';
 There was a bug where feature 'state' wasn't always imported. Further, there