Floating-point literals should store bits in integers, not use host f32/f64. about rspirv

[Jasper-Bekkers]

@eddyb do you have any examples of where this is done wrong? Is it just the constant_f32 functions and LiteralFloat32 etc?

[eddyb]

Right, and loading code like this:

rspirv/rspirv/binary/decoder.rs

Lines 205 to 219 in 719cf08

	/// Decodes and returns the next SPIR-V word as a 32-bit
	/// literal floating point number.
	pub fn float32(&mut self) -> Result<f32> {
	let val = self.word()?;
	Ok(f32::from_bits(val))
	}
	/// Decodes and returns the next two SPIR-V words as a 64-bit
	/// literal floating point number.
	pub fn float64(&mut self) -> Result<f64> {
	let low = u64::from(self.word()?);
	let high = u64::from(self.word()?);
	let val = (high << 32) | low;
	Ok(f64::from_bits(val))
	}

Basically the types f32 and f64 should more or less not show up in rspirv (except maybe for fmt::Debug?).