Test native int ops with Buf creation

RT#128655: https://rt.perl.org/Ticket/Display.html?id=128655
Rakudo fix: rakudo/rakudo@29fdb75a30
            rakudo/rakudo@3d73597556

S32-container/buf.t

@@ -2,7 +2,7 @@ use v6;
 
 use Test;
 
-plan 21;
+plan 22;
 
 # L<S32::Containers/Classes and Roles/"=item Buf">
 
@@ -197,4 +197,8 @@ is-deeply Buf.allocate(10, (1,2,3)).reallocate(0).reallocate(5),
 is-deeply Buf.new(1 xx 2)».join, ("1", "1"),
     'no explosions when hypering .join over a Blob';
 
+# https://rt.perl.org/Ticket/Display.html?id=128655
+is-deeply Buf.new((my int $i = 0x03) +& 0x6), Buf.new(2),
+    'can use native int operations to create a Buf with';
+
 # vim: ft=perl6