This CL adds a generic Event Class to unify common
methods of IC and Map events. The Entry Class for IC
Events and V8Map Class for Map Events inherits from
this generic Event Class.

Bug: v8:10644, v8:10735

Change-Id: I77d68fb40ee0ffbe297fcd1a13c3e2b746938168
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2317309
Commit-Queue: Zeynep Cankara <zcankara@google.com>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Sathya Gunasekaran  <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69066}