Investigate clippy failure on example-shader with glam

Running clippy on example-shader after the glam conversion in #149 results in:

     Compiling example-shader v0.1.0 (/home/runner/work/rust-gpu/rust-gpu/examples/example-shader)
  error: constant runtime array value

https://github.com/EmbarkStudios/rust-gpu/pull/149/checks?check_run_id=1326417262

it is from our codegen but not sure how we are getting it and needs further investigation

The actual failure is due to panicking with a string, and strings are not supported yet. I added a quick ignored test as a reminder to implement it eventually.

rust-gpu/crates/spirv-builder/src/test/basic.rs

Lines 37 to 48 in 0b5ddb6

    
           // TODO: Implement strings to make this compile 
        
           #[test] 
        
           #[ignore] 
        
           fn panic() { 
        
               val(r#" 
        
           #[allow(unused_attributes)] 
        
           #[spirv(fragment)] 
        
           pub fn main() { 
        
               panic!("aaa"); 
        
           } 
        
           "#); 
        
           }

But for why clippy generates code that panics with a string, but normal builds don't, that I have no idea on. I tried investigating for a few hours, and came up with nothing.

I think I managed to get this problem also when building the shader in debug (so not using --release), which likely introduces debug asserts with strings also

I think this is probably fixed with eddyb's work

	// TODO: Implement strings to make this compile
	#[test]
	#[ignore]
	fn panic() {
	val(r#"
	#[allow(unused_attributes)]
	#[spirv(fragment)]
	pub fn main() {
	panic!("aaa");
	}
	"#);
	}