Try to compile time error when trying to make non byte aligned array on js

[Pi-Cla]

Try to detect when someone tries to make a non byte aligned array on Javascript. This compile time error still fails to trigger if the size value is a variable though. So we still need the runtime error in the Javascript template too.

Fixes #1591

[Pi-Cla]

We already de facto do not support this as seen in these lines of the Javascript template:

gleam/compiler-core/templates/prelude.mjs

Lines 164 to 167 in da0d82c

	if (size % 8 != 0) {
	const msg = `Bit arrays must be byte aligned on JavaScript, got size of ${size} bits`;
	throw new globalThis.Error(msg);
	}

So this change will just make that more explicit in certain circumstances

[Pi-Cla]

Also, where should I add tests for these?
(It is sometimes hard to tell where I can add tests for some of my changes such as this one...)

[lpil]

Thank you!!

I would put the tests in https://github.com/gleam-lang/gleam/blob/main/compiler-core/src/javascript/tests/bit_arrays.rs

[lpil]

What happened to these two tests?

[Pi-Cla]

This snapshot correspond to this test:

gleam/compiler-core/src/javascript/tests/bit_arrays.rs

Lines 70 to 78 in f863f0b

	fn explicit_sized() {
	assert_js!(
	r#"
	fn go() {
	<<256:size(4)>>
	}
	"#,
	);
	}

Since the size of this array is being set to 4 it would not be byte aligned and it would cause a runtime error. So instead this code marks that as unsupported and so removes the function it is contained in.

I guess I can rewrite these tests to have a size which is a multiple of 8 instead and also add in some new tests which use not byte aligned bit arrays.

[Pi-Cla]

The tests have been added. I also added extra tests which demonstrate how negatively sized bit arrays are currently handled in both Erlang and Javascript. Which is that for both targets we just assume the developer meant a bit array of size 0.