Restore running precompiled modules with the CLI (#3343)

* Restore running precompiled modules with the CLI

This was accidentally broken when `Module::deserialize` was split out of
`Module::new` long ago, so this adds the detection in the CLI to call
the appropriate method to load the module. This feature is gated behind
an `--allow-precompiled` flag to enable, by default, passing arbitrary
user input to the `wasmtime` command.

Closes #3338

* Fix test on Windows

tests/all/cli_tests.rs

@@ -2,7 +2,7 @@ use anyhow::{bail, Result};
 use std::io::Write;
 use std::path::Path;
 use std::process::{Command, Output};
-use tempfile::NamedTempFile;
+use tempfile::{NamedTempFile, TempDir};
 
 // Run the wasmtime CLI with the provided args and return the `Output`.
 fn run_wasmtime_for_output(args: &[&str]) -> Result<Output> {
@@ -381,3 +381,19 @@ fn exit_with_saved_fprs() -> Result<()> {
     assert!(output.stdout.is_empty());
     Ok(())
 }
+
+#[test]
+fn run_cwasm() -> Result<()> {
+    let td = TempDir::new()?;
+    let cwasm = td.path().join("foo.cwasm");
+    let stdout = run_wasmtime(&[
+        "compile",
+        "tests/all/cli_tests/simple.wat",
+        "-o",
+        cwasm.to_str().unwrap(),
+    ])?;
+    assert_eq!(stdout, "");
+    let stdout = run_wasmtime(&["run", "--allow-precompiled", cwasm.to_str().unwrap()])?;
+    assert_eq!(stdout, "");
+    Ok(())
+}