- Add V8_OS_STRING and V8_TARGET_OS_STRING define
- Add v8-platform logging event
- Add shared-library-end event for faster v8.log processing

Change-Id: Id25a9e704620dbb70042e51a1fb6ed77ca7256bb
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3067219Reviewed-by: Patrick Thier <pthier@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#76040}