VisitWord32EqualImpl was checking for inputs of type
kCompressedHeapConstant, but it can also sometimes have inputs of type
kHeapConstant. In either case, we can check for whether to do a load
from the roots array. This improves Octane score by about 3% (or about
1.5% if --no-opt is specified).

Bug: v8:8948
Change-Id: Iab6c0b1dacd96c74e4cfb54c772aa92e5baf00ff
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2213081
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67981}