[parser] Preallocate param initialization block with entry per complex parameter

Change-Id: I33426cdbec284f3f2f8d80b29788067efc56226b
Reviewed-on: https://chromium-review.googlesource.com/c/1267942Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56446}

src/parsing/parser.cc

@@ -2787,7 +2787,7 @@ Block* Parser::BuildParameterInitializationBlock(
   DCHECK(!parameters.is_simple);
   DCHECK(scope()->is_function_scope());
   DCHECK_EQ(scope(), parameters.scope);
-  Block* init_block = factory()->NewBlock(1, true);
+  Block* init_block = factory()->NewBlock(parameters.num_parameters(), true);
   int index = 0;
   for (auto parameter : parameters.params) {
     DeclarationDescriptor descriptor;