3d rendered bezier curve args get overwritten

[unjust]

Reorder argument setting to bezier in 3d mode, so original arg values aren't overwritten.

In the code below:
https://github.com/processing/p5.js/blob/master/src/webgl/3d_primitives.js#L1088
x2 should = z1, but assigning y2 = x2 afterwards is basically assigning y2 = z1.

Demoing the bug:

Having a bezier with all z coords set to 0 should result in the same curve as a bezier with no z;

Nature of issue?

• [x ] Found a bug
• Existing feature enhancement
• New feature request

Most appropriate sub-area of p5.js?

• Color
• Core/Environment/Rendering
• Data
• Events
• Image
• IO
• Math
• Typography
• Utilities
• WebGL
• Other (specify if possible)

Which platform were you using when you encountered this?

• Mobile/Tablet (touch devices)
• Desktop/Laptop
• Others (specify if possible)

Details about the bug:

• p5.js version:
• Web browser and version:
• Operating System:
• Steps to reproduce this:

Feature enhancement details:

New feature details:

[unjust]

Fix in PR #3343

@Spongman might be interested in this.