Implement Yul to LLVM IR compilation benchmarks (#407)

# Description

Closes [#404](https://github.com/paritytech/revive/issues/404)

Adds compilation time benchmarks for:

* Parsing of Yul source code -> AST Object
* Lowering of AST Object -> LLVM IR (unoptimized)

The benchmarks can be run from the root via:

```sh
# Run all benchmarks in the revive-yul crate (parsing + lowering)
make bench-yul
```

HTML reports will be generated under `target/criterion`, and a summary
of the results at
[crates/yul/BENCHMARKS_PARSE_M4PRO.md](https://github.com/paritytech/revive/blob/lj/compilation-benchmarks-yul/crates/yul/BENCHMARKS_PARSE_M4PRO.md)
and
[crates/yul/BENCHMARKS_LOWER_M4PRO.md](https://github.com/paritytech/revive/blob/lj/compilation-benchmarks-yul/crates/yul/BENCHMARKS_LOWER_M4PRO.md)
(currently from running on a Mac M4 Pro).

---------

Co-authored-by: xermicus <cyrill@parity.io>

crates/llvm-context/src/polkavm/context/mod.rs

@@ -256,6 +256,22 @@ impl<'ctx> Context<'ctx> {
         }
     }
 
+    /// Initializes a new dummy LLVM context.
+    ///
+    /// Omits the LLVM module initialization; use this only in tests and benchmarks.
+    pub fn new_dummy(
+        llvm: &'ctx inkwell::context::Context,
+        optimizer_settings: OptimizerSettings,
+    ) -> Self {
+        Self::new(
+            llvm,
+            llvm.create_module("dummy"),
+            Optimizer::new(optimizer_settings),
+            Default::default(),
+            Default::default(),
+        )
+    }
+
     /// Builds the LLVM IR module, returning the build artifacts.
     pub fn build(
         self,

crates/llvm-context/src/polkavm/context/tests.rs

@@ -1,33 +1,21 @@
 //! The LLVM IR generator context tests.
 
 use crate::optimizer::settings::Settings as OptimizerSettings;
-use crate::optimizer::Optimizer;
 use crate::polkavm::context::attribute::Attribute;
 use crate::polkavm::context::Context;
 use crate::PolkaVMTarget;
 
-pub fn create_context(
-    llvm: &inkwell::context::Context,
-    optimizer_settings: OptimizerSettings,
-) -> Context<'_> {
+/// Initializes the LLVM compiler backend.
+fn initialize_llvm() {
     crate::initialize_llvm(PolkaVMTarget::PVM, "resolc", Default::default());
-
-    let module = llvm.create_module("test");
-    let optimizer = Optimizer::new(optimizer_settings);
-
-    Context::new(
-        llvm,
-        module,
-        optimizer,
-        Default::default(),
-        Default::default(),
-    )
 }
 
 #[test]
 pub fn check_attribute_null_pointer_is_invalid() {
+    initialize_llvm();
+
     let llvm = inkwell::context::Context::create();
-    let mut context = create_context(&llvm, OptimizerSettings::cycles());
+    let mut context = Context::new_dummy(&llvm, OptimizerSettings::cycles());
 
     let function = context
         .add_function(
@@ -51,8 +39,10 @@ pub fn check_attribute_null_pointer_is_invalid() {
 
 #[test]
 pub fn check_attribute_optimize_for_size_mode_3() {
+    initialize_llvm();
+
     let llvm = inkwell::context::Context::create();
-    let mut context = create_context(&llvm, OptimizerSettings::cycles());
+    let mut context = Context::new_dummy(&llvm, OptimizerSettings::cycles());
 
     let function = context
         .add_function(
@@ -76,8 +66,10 @@ pub fn check_attribute_optimize_for_size_mode_3() {
 
 #[test]
 pub fn check_attribute_optimize_for_size_mode_z() {
+    initialize_llvm();
+
     let llvm = inkwell::context::Context::create();
-    let mut context = create_context(&llvm, OptimizerSettings::size());
+    let mut context = Context::new_dummy(&llvm, OptimizerSettings::size());
 
     let function = context
         .add_function(
@@ -101,8 +93,10 @@ pub fn check_attribute_optimize_for_size_mode_z() {
 
 #[test]
 pub fn check_attribute_min_size_mode_3() {
+    initialize_llvm();
+
     let llvm = inkwell::context::Context::create();
-    let mut context = create_context(&llvm, OptimizerSettings::cycles());
+    let mut context = Context::new_dummy(&llvm, OptimizerSettings::cycles());
 
     let function = context
         .add_function(
@@ -126,8 +120,10 @@ pub fn check_attribute_min_size_mode_3() {
 
 #[test]
 pub fn check_attribute_min_size_mode_z() {
+    initialize_llvm();
+
     let llvm = inkwell::context::Context::create();
-    let mut context = create_context(&llvm, OptimizerSettings::size());
+    let mut context = Context::new_dummy(&llvm, OptimizerSettings::size());
 
     let function = context
         .add_function(