- Shift opcode numbers for asmjs-compat opcodes
 - Add --experimental-wasm-se flag to gate sign extension opccodes
 - Fix codegen for ia32 movsx instructions

Bug: v8:6532
Change-Id: If7c9eff5ac76d24496effb2314ae2601bb8bba85
Reviewed-on: https://chromium-review.googlesource.com/838403
Commit-Queue: Deepti Gandluri <gdeepti@chromium.org>
Reviewed-by: Bill Budge <bbudge@chromium.org>
Reviewed-by: Ben Titzer <titzer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50875}