feat: add overloaded IO.print methods accepting 2-16 arguments and printList_ helper

Add 15 static overloads of IO.print in builtin/io.wren and src/wren_io.c, each delegating to a new private printList_ method that iterates over a list of objects. Update all benchmark and test files to use the new multi-argument syntax, removing explicit .toString calls and string concatenation. Add a comprehensive test/io/print.wren verifying single-argument return value, multi-argument null return, and concatenation of up to 16 arguments.

test/constructor/superclass.wren

@@ -1,6 +1,6 @@
 class A {
   new(arg) {
-    IO.print("new A " + arg)
+    IO.print("new A ", arg)
     _field = arg
   }
 
@@ -10,7 +10,7 @@ class A {
 class B is A {
   new(arg1, arg2) {
     super(arg2)
-    IO.print("new B " + arg1)
+    IO.print("new B ", arg1)
     _field = arg1
   }