add columns to debug information (#362)

- Add column numbers to debug information.
- Do not build allocas at entry for now.

---------

Signed-off-by: Cyrill Leutwiler <bigcyrill@hotmail.com>

crates/llvm-context/src/polkavm/context/function/runtime/runtime_code.rs

@@ -48,6 +48,7 @@ where
             function_type,
             0,
             Some(inkwell::module::Linkage::External),
+            None,
         )?;
 
         self.inner.declare(context)