Support -Zmin-function-alignment

[bjorn3]

This was added in rust-lang/rust#134030. This will require a minor change to cranelif-object to be able to increase the alignment at https://github.com/bytecodealliance/wasmtime/blob/7f9049b9df84a748d0f7b4024e29b26014923c28/cranelift/object/src/backend.rs#L378-L380

[bjorn3]

Once bytecodealliance/wasmtime#10391 is merged this can be implemented using:

diff --git a/src/lib.rs b/src/lib.rs
index caaa0696..bc8fba81 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -278,6 +278,12 @@ fn build_isa(sess: &Session) -> Arc<dyn TargetIsa + 'static> {
 
     flags_builder.set("enable_llvm_abi_extensions", "true").unwrap();
 
+    if let Some(min_function_alignment) = sess.opts.unstable_opts.min_function_alignment {
+        flags_builder
+            .set("log2_min_function_alignment", &min_function_alignment.bytes().ilog2().to_string())
+            .unwrap();
+    }
+
     use rustc_session::config::OptLevel;
     match sess.opts.optimize {
         OptLevel::No => {