Add a compile command to Wasmtime.

This commit adds a `compile` command to the Wasmtime CLI.

The command can be used to Ahead-Of-Time (AOT) compile WebAssembly modules.

With the `all-arch` feature enabled, AOT compilation can be performed for
non-native architectures (i.e. cross-compilation).

The `Module::compile` method has been added to perform AOT compilation.

A few of the CLI flags relating to "on by default" Wasm features have been
changed to be "--disable-XYZ" flags.

A simple example of using the `wasmtime compile` command:

```text
$ wasmtime compile input.wasm
$ wasmtime input.cwasm
```

cranelift/codegen/src/isa/x64/mod.rs

@@ -9,7 +9,7 @@ use crate::isa::Builder as IsaBuilder;
 use crate::machinst::{compile, MachBackend, MachCompileResult, TargetIsaAdapter, VCode};
 use crate::result::CodegenResult;
 use crate::settings::{self as shared_settings, Flags};
-use alloc::boxed::Box;
+use alloc::{borrow::ToOwned, boxed::Box, string::String, vec::Vec};
 use core::hash::{Hash, Hasher};
 use regalloc::{PrettyPrint, RealRegUniverse, Reg};
 use target_lexicon::Triple;
@@ -85,6 +85,17 @@ impl MachBackend for X64Backend {
         &self.flags
     }
 
+    fn enabled_isa_flags(&self) -> Vec<String> {
+        self.x64_flags
+            .iter_enabled()
+            .map(ToOwned::to_owned)
+            .collect()
+    }
+
+    fn is_flag_enabled(&self, flag: &str) -> bool {
+        self.x64_flags.is_enabled(flag)
+    }
+
     fn hash_all_flags(&self, mut hasher: &mut dyn Hasher) {
         self.flags.hash(&mut hasher);
         self.x64_flags.hash(&mut hasher);