Updates CSA::TryToIntptr to handle array indices that are less than
INT_MAX which allows to handle string keys in the ICs.

Updates ICs to go monomorphic for string keys that are array indices.

Updates Turbofan to handle array indices when lowering element access.

Change-Id: Ibdde20130e075d0d645ab4a8266a968335eaad84
Bug: v8:9449
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1813018Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Sathya Gunasekaran  <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64320}