turn an RC entry by TimToady++ into an integration tests

Very interesting for us, because it makes nom segfault

integration/lazy-bentley-generator.t

@@ -0,0 +1,24 @@
+use Test;
+
+sub bentley_clever($seed) {
+    constant $mod = 1_000_000_000;
+
+    my @state;
+
+    my @seed = ($seed % $mod, 1, (* - *) % $mod ... *)[^55];
+    @state = @seed[ 34, (* + 34 ) % 55 ... 0 ];
+
+    subrand() for 55 .. 219;
+
+    sub subrand() {
+        push @state, (my $x = (@state.shift - @state[*-24]) % $mod);
+        $x;
+    }
+
+    &subrand ... *;
+}
+
+my @sr := bentley_clever(292929);
+is @sr[^6].join('|'),
+   '467478574|512932792|539453717|20349702|615542081|378707948',
+   'can do funny things with lazy series';