[parser] Reserve initial vector memory rather than default construction

The constructor that accepts a size for vector default initializes the
elements. Using reserve() instead avoids this but still ensures the
capacity.

Change-Id: I8effb62ba1f9598a0081c2c959b2f7a5d6c587e6
Reviewed-on: https://chromium-review.googlesource.com/1186407Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55348}

src/parsing/parser-base.h

@@ -1593,12 +1593,13 @@ ParserBase<Impl>::FunctionState::FunctionState(
       outer_function_state_(*function_state_stack),
       scope_(scope),
       destructuring_assignments_to_rewrite_(scope->zone()),
-      reported_errors_(16, scope_->zone()),
+      reported_errors_(scope_->zone()),
       dont_optimize_reason_(BailoutReason::kNoReason),
       next_function_is_likely_called_(false),
       previous_function_was_likely_called_(false),
       contains_function_or_eval_(false) {
   *function_state_stack = this;
+  reported_errors_.reserve(16);
   if (outer_function_state_) {
     outer_function_state_->previous_function_was_likely_called_ =
         outer_function_state_->next_function_is_likely_called_;