[wasm] Publish new code from the background threads.

R=clemensh@chromium.org
BUG=v8:7921

Change-Id: Ib86cb5f742907b6e54365827facfc765867ca22e
Reviewed-on: https://chromium-review.googlesource.com/1156384Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54985}

src/compiler/wasm-compiler.cc

@@ -5168,6 +5168,7 @@ void TurbofanWasmCompilationUnit::ExecuteCompilation() {
     }
     if (ok_) wasm_code_ = info.wasm_code();
   }
+  if (ok_) wasm_unit_->native_module()->PublishCode(wasm_code_);
 }
 
 wasm::WasmCode* TurbofanWasmCompilationUnit::FinishCompilation(
@@ -5190,8 +5191,6 @@ wasm::WasmCode* TurbofanWasmCompilationUnit::FinishCompilation(
 
     return nullptr;
   }
-
-  wasm_unit_->native_module()->PublishCode(wasm_code_);
   return wasm_code_;
 }