llvm-context: lazy handling of function arguments and immutable data (#282)

- Lazily load function arguments so that they can be passed as pointers.
- Lazily call the immutable store function to avoid storing zero sized
immutable data.

---------

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

crates/solidity/src/yul/parser/statement/if_conditional.rs

@@ -57,7 +57,7 @@ where
             .condition
             .into_llvm(context)?
             .expect("Always exists")
-            .to_llvm()
+            .access(context)?
             .into_int_value();
         let condition = context.builder().build_int_z_extend_or_bit_cast(
             condition,