[parser] Tentatively enable FLAG_preparser_scope_analysis.

... mainly to get more canary coverage.

BUG=v8:5516

Change-Id: I323e7ee867ff2340d28e55ff249298d8a91fbde1
Reviewed-on: https://chromium-review.googlesource.com/649207Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47803}

src/flag-definitions.h

@@ -866,7 +866,7 @@ DEFINE_BOOL(lazy_inner_functions, true, "enable lazy parsing inner functions")
 DEFINE_BOOL(aggressive_lazy_inner_functions, false,
             "even lazier inner function parsing")
 DEFINE_IMPLICATION(aggressive_lazy_inner_functions, lazy_inner_functions)
-DEFINE_BOOL(preparser_scope_analysis, false,
+DEFINE_BOOL(preparser_scope_analysis, true,
             "perform scope analysis for preparsed inner functions")
 DEFINE_IMPLICATION(preparser_scope_analysis, aggressive_lazy_inner_functions)