[wasm][fuzzer] Temporarily disable gc fuzzing

We temporarily disable fuzzing for wasm-gc until we update the fuzzer
to the isorecursive hybrid type system.

Bug: chromium:1291959
Change-Id: I2238c37bc49cbac2bf1c4085815a2283db982ab3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3423782Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78869}

test/fuzzer/wasm-fuzzer-common.cc

@@ -799,12 +799,15 @@ void WasmExecutionFuzzer::FuzzWasmModule(base::Vector<const uint8_t> data,
   // Control whether Liftoff or the interpreter will be used as the reference
   // tier.
   // TODO(thibaudm): Port nondeterminism detection to arm.
-#if defined(V8_TARGET_ARCH_X64) || defined(V8_TARGET_ARCH_X86)
-  bool liftoff_as_reference = configuration_byte & 1;
-#else
+  /* TODO(manoskouk): Temporarily disable liftoff-as-reference, i.e., wasm-gc
+     fuzzing until we update the fuzzer to isorecursive types.
+  #if defined(V8_TARGET_ARCH_X64) || defined(V8_TARGET_ARCH_X86)
+    bool liftoff_as_reference = configuration_byte & 1;
+  #else
+    bool liftoff_as_reference = false;
+  #endif
+  */
   bool liftoff_as_reference = false;
-#endif
-
   FlagScope<bool> turbo_mid_tier_regalloc(&FLAG_turbo_force_mid_tier_regalloc,
                                           configuration_byte == 0);