[wasm][cleanup] Remove unused field from ModuleDecoderImpl

Change-Id: Iad4e33df76ce95b7f5543496fe1d2d7239f33c30
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2775566
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73558}

src/wasm/module-decoder.cc

@@ -1340,10 +1340,6 @@ class ModuleDecoderImpl : public Decoder {
                     kLastKnownModuleSection,
                 "not enough bits");
   WasmError intermediate_error_;
-  // Set of type offsets discovered in field types during type section decoding.
-  // Since struct types may be recursive, this is used for checking and error
-  // reporting once the whole type section is parsed.
-  std::unordered_map<uint32_t, int> deferred_check_type_index_;
   ModuleOrigin origin_;
 
   ValueType TypeOf(const WasmInitExpr& expr) {