totally speed up prefix:<->(Complex), or so I hope.

This patch replaces one line of code with 10, but it should avoid any box and unbox operation.
Doing the same with operators will be rather straight-forward, but quite repetitive.
I wonder if it could be automated. I have read about tools called "compilers" that could
make such a task much easier... :-)

src/core/Complex.pm

@@ -62,7 +62,18 @@ my class Complex is Numeric {
 }
 
 multi sub prefix:<->(Complex \$a) {
-    Complex.new(-$a.re, -$a.im);
+    my $new := nqp::create(Complex);
+    nqp::bindattr_n( $new, Complex, '$!re',
+        nqp::neg_n(
+            nqp::getattr_n(pir::perl6_decontainerize__PP($a), Complex, '$!re')
+        )
+    );
+    nqp::bindattr_n( $new, Complex, '$!im',
+        nqp::neg_n(
+            nqp::getattr_n(pir::perl6_decontainerize__PP($a), Complex, '$!im')
+        )
+    );
+    $new;
 }
 
 multi sub infix:<+>(Complex \$a, Complex \$b) {