Math.max and Math.min only accept two parameters


## *What* is wrong?
Using `Math.max` with more than two parameters causes the GPU kernel build to fail.

## *How* do we replicate the issue?
```
const gpu = new GPU({ mode: 'gpu' });
const kernel = gpu.createKernel(function() {
return Math.max(0, 1, 2);
}).setOutput([1]);
kernel();
```
And observe the output error
`gpu-browser.js:14913 Uncaught Error: Error compiling fragment shader: ERROR: 0:457: 'max' : no matching overloaded function found`. Replacing `0, 1, 2` with `0, 1` (or any other two numbers) leads to the function behaving as expected. The same is true of `Math.min`.
JS Fiddle: [https://jsfiddle.net/TomWyllie/opdg95kb/](https://jsfiddle.net/TomWyllie/opdg95kb/)

GPU.js 2.9.4
GPU: NVIDIA GeForce GTX 1060 3GB
Nvidia Driver 446.14
Google Chrome Version 83.0.4103.97 (Official Build) (64-bit)
Windows 10

## *How* important is this (1-5)?
2, it's very easy (but pretty messy) to workaround by using `Math.max(x, Math.max(y, Math.max(z, t)));` or similar, but that is pretty ugly. My understanding is that the [spec](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/max) allows arbitrarily many parameters.

## Other Comments
I'm beginning to think there might be something deeper wrong with GPU.js on my machine given this issue and the other I filed several days ago (#617) must be very common use cases and surely lots of other people would be having these same problems... any thoughts appreciated.