Remove always-on logging from fuzz targets (#878)

Now that the `cargo fuzz` tooling is better, it is easier to reproduce failures,
and we don't need to be super paranoid about logging here.

fuzz/fuzz_targets/instantiate.rs

@@ -2,8 +2,8 @@
 
 use libfuzzer_sys::fuzz_target;
 use wasmtime::Strategy;
-use wasmtime_fuzzing::{oracles, with_log_wasm_test_case};
+use wasmtime_fuzzing::oracles;
 
 fuzz_target!(|data: &[u8]| {
-    with_log_wasm_test_case!(data, |data| oracles::instantiate(data, Strategy::Auto,));
+    oracles::instantiate(data, Strategy::Auto);
 });