Godot: Additional lines drawn when using draw_polygon

[TicklesTheBrain]

Godot version: Godot 3.2 Beta 3/4

OS/device including version: Windows 10

Issue description:
There are additional lines when drawing a concave polygon, that were not there in Beta 2 and all previous Godot versions

Steps to reproduce:
Draw a shape with a cutout shape inside it as a single concave polygon.
Or run the attached repro project.
Try the same in beta 3 and beta 2 and compare the results.

Minimal reproduction project:
bug_repro_proj.zip

Screenshots of repro project in Beta 2

And that same project in Beta 3 and beyond:

[MadEqua]

I ran a bisect and it seems this was introduced on this commit:

https://github.com/godotengine/godot/commit/e6ebc43d725710f69094afa6ff47d91e50cce1ad?diff=unified#diff-e64fc7b93ef7deefed9e5978c3615901L825-L829

by drawing lines for AA using the indices. I'm not sure what to do, so I'll leave this here open for discussion.

[clayjohn]

CC @pouleyKetchoupp

[pouleyKetchoupp]

@TicklesTheBrain This case will be fixed with PR #34726. Note that you also need to disable hdr in your example project for antialiasing to work properly.