It's cheaper to materialize heap constants by loading from the roots
array instead of embedding the constant into the instruction stream, at
least on x64, arm and arm64.

Drive-by-fix: Also cleanup the materialize constant from frame
optimization.

R=dcarney@chromium.org

Review URL: https://codereview.chromium.org/1088913002

Cr-Commit-Position: refs/heads/master@{#27818}