JavaClassWrapper: Improve handling of typed array arguments

[dsnopek]

Fixes #102712

There are 3 issues that come from that:

• Method selection doesn't take typed arrays (including the Packed*Array types) into account when selected an overloaded method
• [x] vararg methods aren't supported
• Arrays of JavaObjects aren't supported (this one I noticed while working on this)

So far, this PR only fixes the first one, which is why this is currently marked as DRAFT.

UPDATE: All the issues are fixed now in my testing!

UPDATE 2: I ended up deciding to remove the explicit support for varargs - see this comment.

[dsnopek]

I've now got all the issues fixed in my testing!

However, this does change quite a large amount of code, and will need a thorough review.

[dsnopek]

After sleeping on this, I've decided to remove the explicit varargs support, and just treat Java varargs methods as having a final array parameter (which is contrary to what I originally wrote here).

While implementing Java varargs as GDScript varargs makes for more idiomatic GDScript code, it creates problems with selecting the correct overridden method, since varargs in GDScript are untyped whereas in Java they are typed. This would make it impossible to distinguish between these two methods from GDScript:

        @JvmStatic
        fun testMethod(int: Int, vararg args: String): String {
            return "String varargs: " + args.contentToString()
        }

        @JvmStatic
        fun testMethod(int: Int, vararg args: Int): String {
            return "Int varargs: " + args.contentToString()
        }

... whereas, if we treat that final argument as a normal array, you can use either Array[String] or Array[int] in GDScript to target one or the other.

So, that's how it works now in my latest push! (I still have previous varargs approach in a branch, in case we want to go back to it.)

This also makes the PR much smaller and easier to review, perhaps making it more likely we could sneak it in for Godot 4.4?

cc @m4gr3d @syntaxerror247