Move rewriting, scope analysis, and internalization, to be unconditional
operations done after parsing rather than a separate compile phase. This
removes some of the complexity about rememberering when to call
Compiler::Analyze, and makes these paths a bit more uniform.

Also, forbid allocating any more AST strings after AstValueFactory
internalization, by nulling out the Zone. Add an InternalizePartial
method which doesn't null out the zone for those cases where we do want
to be able to allocate after internalizing (e.g. internalization before
scope analysis).

Change-Id: Id444246d8362a1d169baf664fc37657d9576fd96
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2182458Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67608}