Add initial differential fuzzing

Part of #611

fuzz/Cargo.toml

@@ -39,3 +39,7 @@ name = "api_calls"
 path = "fuzz_targets/api_calls.rs"
 test = false
 doc = false
+
+[[bin]]
+name = "differential"
+path = "fuzz_targets/differential.rs"

fuzz/fuzz_targets/differential.rs

@@ -0,0 +1,13 @@
+#![no_main]
+
+use libfuzzer_sys::fuzz_target;
+use wasmtime_fuzzing::{generators, oracles};
+
+fuzz_target!(|data: (
+    generators::DifferentialConfig,
+    generators::DifferentialConfig,
+    generators::WasmOptTtf
+)| {
+    let (lhs, rhs, wasm) = data;
+    oracles::differential_execution(&wasm, &[lhs, rhs]);
+});