Inferring the language mode involves iterating the stack to find the
closure. This is an expensive operation and should be done only when
required. This cl changes the implementation to infer the language
mode only when we can't defer it any further. Currently, we infer the
language mode when throwing an exception or when passing this
information to PropertyCallbackArguments.

This cl also changes the language mode parameter to SetProperty
related methods to Maybe<ShouldThrow>. We only use the language mode to
decide if we need to throw and using ShouldThrow instead of language
mode simplifies the code by avoiding conversions from Maybe<ShouldThrow>
to Maybe<LanguageMode> and vice-versa.

Bug: v8:8580, chromium:923820, chromium:925289
Change-Id: I72497497f62fe0d86fcecd57b06b3183b7531f7b
Reviewed-on: https://chromium-review.googlesource.com/c/1425912
Commit-Queue: Mythri Alle <mythria@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59094}