Fix a typo in the parsing regex.

In the pattern for the delimiter sequence one
of the null bytes was missing the \x backslash modifier,
turning it from \x00 to \00. The regex as a whole still seems
to have worked, though, which is why this could go unnoticed for
so long.

shadow_tune.pl

@@ -43,7 +43,7 @@ sub find_game_resources {
 
 sub asset_dump {
 
-    my $delimiter = qr/\x00*\x02\x00{3}\x0E\00{7}\x02\x00{3}/;
+    my $delimiter = qr/\x00*\x02\x00{3}\x0E\x00{7}\x02\x00{3}/;
     my ($op_params, $assets_content, $sound_meta_start) = @_;
     my @track_list;