There are some cases where we can ignore some truncations or
change nodes for Smi Untagging, when we are using 31 bit smis
in 64 bit architectures.

Updated DecompressionOptimizer to match the new pattern.

Change-Id: I89d34407e6f780ec0399cd427cf9d3e24ee5669a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1889877
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64909}