[wasm] Fix redundant reify of error

In its destructor, the ErrorThrower already reifies exceptions and
throws them if an error has been set.

R=mtrofin@chromium.org

Change-Id: I17d7a6d300fe4a5860431f214746d053eaf9f104
Reviewed-on: https://chromium-review.googlesource.com/497467
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45153}

src/wasm/wasm-module.cc

@@ -3191,10 +3191,9 @@ bool LazyCompilationOrchestrator::CompileFunction(
   deopt_data->set(1, Smi::FromInt(func_index));
   code->set_deoptimization_data(*deopt_data);
 
-  if (thrower.error()) {
-    if (!isolate->has_pending_exception()) isolate->Throw(*thrower.Reify());
-    return false;
-  }
+  // If we have a pending error, just return. The ErrorThrower will set the
+  // pending exception in its destructor.
+  if (thrower.error()) return false;
 
   DCHECK_EQ(Builtins::kWasmCompileLazy,
             Code::cast(compiled_module->code_table()->get(func_index))