- Dehandlify ScopeInfo::ContextSlotIndex
- Dehandlify ScriptContextTable::Lookup
- Introduce function-kind.h with range-based helper methods
- Spread usage of Scope::is_script_scope and friends

Change-Id: I8ed1d82cc5bb9ea3fce856e16e9eafe194fb57ba
Reviewed-on: https://chromium-review.googlesource.com/c/1430100Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59120}