We found there are redundant load context operations in
some bytecode array.

like this:
LdaImmutableCurrentContextSlot [1]
Star0
......   (don’t edit accumulator)
LdaImmutableCurrentContextSlot [1]
Star1
Add r1

In that case, we could modify this bytecode array as:
LdaImmutableCurrentContextSlot [1]
Star0
......   (don’t edit accumulator)
Add r0

This CL will elide these redundant bytecodes
(LdaImmutableCurrentContextSlot and Star1), because there is no
side effect for loading context, and this context slot is immutable.

Change-Id: Ia26f4b934d3bd1d48c50c0c4699ba7942939991c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3816221Reviewed-by: Shu-yu Guo <syg@chromium.org>
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82641}