There are a same name field equivalence_id_ in both
BytecodeRegisterOptimizer and RegisterInfo, but one of them is int,
another one is uint32_t, it's better to change them as same type
to avoid addtional or potential type casting.

Change-Id: I509f850d82a9a0fc30168fae83a0bd6565b7000e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3811138Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Wenqin Yang <wenqin.yang@intel.com>
Cr-Commit-Position: refs/heads/main@{#82214}