[wasm] Do not log imported function code

The wrappers for imports are not accessible through the code() accessor,
so avoid tracing them for now.

BUG=chromium:844745
R=ahaas@chromium.org

Change-Id: I63fe447091ba3c202e3ffcfddfa645049a0b83cf
Reviewed-on: https://chromium-review.googlesource.com/1068739
Commit-Queue: Ben Titzer <titzer@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53280}

src/wasm/wasm-objects.cc

@@ -1552,8 +1552,12 @@ void WasmCompiledModule::LogWasmCodes(Isolate* isolate) {
 
   wasm::NativeModule* native_module = GetNativeModule();
   if (native_module == nullptr) return;
+  // TODO(titzer): we skip the logging of the import wrappers
+  // here, but they should be included somehow.
+  const uint32_t start =
+      native_module->shared_module_data()->module()->num_imported_functions;
   const uint32_t number_of_codes = native_module->function_count();
-  for (uint32_t i = 0; i < number_of_codes; i++) {
+  for (uint32_t i = start; i < number_of_codes; i++) {
     wasm::WasmCode* code = native_module->code(i);
     if (code == nullptr) continue;
     code->LogCode(isolate);