Fuzz the tail call proposal on OSS-Fuzz (bytecodealliance#8591)

This was disabled historically before it was fully implemented, but
Wasmtime now fully implements it, so enable it for fuzzing.

crates/fuzzing/src/generators/config.rs

@@ -395,10 +395,6 @@ impl<'a> Arbitrary<'a> for Config {
             config.disable_unimplemented_winch_proposals();
         }
 
-        // This is pulled from `u` by default via `wasm-smith`, but Wasmtime
-        // doesn't implement this yet, so forcibly always disable it.
-        config.module_config.config.tail_call_enabled = false;
-
         // Wasm-smith implements the most up-to-date version of memory64 where
         // it supports 64-bit tables as well, but Wasmtime doesn't support that
         // yet, so disable the memory64 proposal in fuzzing for now.