[x64] Recognize MOVSXBL.

TEST=mjsunit/asm
R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/728103007

Cr-Commit-Position: refs/heads/master@{#25386}
Hydrogen should recognize literal smi arrays as fast literals.

R=hpayer@chromium.org

Review URL: https://codereview.chromium.org/726423002

Cr-Commit-Position: refs/heads/master@{#25387}
[turbofan] Avoid useless sign extension after sign extended load.

TEST=unittests
R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/735623002

Cr-Commit-Position: refs/heads/master@{#25388}
Allow stepping into Promise handlers.

BUG=chromium:432468
R=yangguo@chromium.org, adamk@chromium.org, arv@chromium.org
LOG=N

Review URL: https://codereview.chromium.org/734163002

Cr-Commit-Position: refs/heads/master@{#25389}