Junction bind failover.

Gets almost all of the junction tests passing that to on Rakudo Parrot
as well as helping many other test files that depend on this somehow.

src/vm/jvm/Perl6/Ops.nqp

@@ -50,10 +50,21 @@ $ops.add_hll_op('perl6', 'p6bindsig', -> $qastcomp, $op {
     $il.append(JAST::Instruction.new( :op('aload'), '__args' ));
     $il.append(JAST::Instruction.new( :op('invokestatic'), $TYPE_P6OPS,
         "p6bindsig", $TYPE_CSD, $TYPE_TC, $TYPE_CSD, "[$TYPE_OBJ" ));
+    $il.append(JAST::Instruction.new( :op('dup') ));
+
+    my $natlbl := JAST::Label.new( :name('p6bindsig_no_autothread') );
+    $il.append(JAST::Instruction.new( :op('ifnonnull'), $natlbl ));
+    $il.append(JAST::Instruction.new( :op('aload'), 'cf' ));
+    $il.append(JAST::Instruction.new( :op('invokevirtual'),
+        $TYPE_CF, 'leave', 'Void' ));
+    $il.append(JAST::Instruction.new( :op('return') ));
+    $il.append($natlbl);
+
     $il.append(JAST::Instruction.new( :op('astore'), 'csd' ));
     $il.append(JAST::Instruction.new( :op('aload_1') ));
     $il.append(JAST::Instruction.new( :op('getfield'), $TYPE_TC, 'flatArgs', "[$TYPE_OBJ" ));
     $il.append(JAST::Instruction.new( :op('astore'), '__args' ));
+
     $ops.result($il, $RT_VOID);
 });
 $ops.map_classlib_hll_op('perl6', 'p6isbindable', $TYPE_P6OPS, 'p6isbindable', [$RT_OBJ, $RT_OBJ], $RT_INT, :tc);

src/vm/jvm/runtime/org/perl6/rakudo/Ops.java

@@ -270,7 +270,15 @@ public static CallSiteDescriptor p6bindsig(ThreadContext tc, CallSiteDescriptor
             case Binder.BIND_RESULT_FAIL:
                 throw ExceptionHandling.dieInternal(tc, error[0]);
             case Binder.BIND_RESULT_JUNCTION:
-                throw ExceptionHandling.dieInternal(tc, "Junction re-dispatch NYI");
+                /* Invoke the auto-threader. */
+                csd = csd.injectInvokee(tc, args, cf.codeRef.codeObject);
+                args = tc.flatArgs;
+                org.perl6.nqp.runtime.Ops.invokeDirect(tc, gcx.AutoThreader, csd, args);
+                org.perl6.nqp.runtime.Ops.return_o(
+                    org.perl6.nqp.runtime.Ops.result_o(cf), cf);
+
+                /* Return null to indicate immediate return to the routine. */
+                return null;
         }
 
         /* The binder may, for a variety of reasons, wind up calling Perl 6 code and overwriting flatArgs, so it needs to be set at the end to return reliably */