Disable wide-arithmetic fuzzing in wasmi

Due to bytecodealliance#10418 I believe there's a bug in wasmi for now, so disable
temporarily until it's updated with a fix.

Closes bytecodealliance#10418

Author: alexcrichton

crates/fuzzing/src/oracles/diff_wasmi.rs

@@ -20,6 +20,10 @@ impl WasmiEngine {
         config.exceptions_enabled = false;
         config.gc_enabled = false;
 
+        // FIXME: currently wasmi has a bug in wide-arithmetic (see #10418), so
+        // disable it temporarily.
+        config.wide_arithmetic_enabled = false;
+
         let mut wasmi_config = wasmi::Config::default();
         wasmi_config
             .consume_fuel(false)