Validate functions in parallel in Module::validate (#3394)

We already validate wasm functions in parallel when compiling a module,
but the same parallelism wasn't available to the `Module::validate` API.
This commit peforms a minor tweak to the validate-the-whole-module API
to validate all functions in parallel in the same manner that module
compilation does.

crates/wasmtime/src/module.rs

@@ -8,7 +8,7 @@ use std::fs;
 use std::mem;
 use std::path::Path;
 use std::sync::Arc;
-use wasmparser::Validator;
+use wasmparser::{Parser, ValidPayload, Validator};
 use wasmtime_environ::{ModuleEnvironment, ModuleIndex, PrimaryMap};
 use wasmtime_jit::{CompiledModule, CompiledModuleInfo, MmapVec, TypeTables};
 
@@ -593,7 +593,15 @@ impl Module {
     pub fn validate(engine: &Engine, binary: &[u8]) -> Result<()> {
         let mut validator = Validator::new();
         validator.wasm_features(engine.config().features);
-        validator.validate_all(binary)?;
+
+        let mut functions = Vec::new();
+        for payload in Parser::new(0).parse_all(binary) {
+            if let ValidPayload::Func(a, b) = validator.payload(&payload?)? {
+                functions.push((a, b));
+            }
+        }
+
+        engine.run_maybe_parallel(functions, |(mut validator, body)| validator.validate(&body))?;
         Ok(())
     }