port 025d476c (r32906)

  original commit message:
  Adds a slot for the bytecode offset to interpreter stack frames and
  saves it on calls, and restores after calls.

  Also fixes RawMachineAssembler::Return() to call MergeControlToEnd.

BUG=

Review URL: https://codereview.chromium.org/1535613003

Cr-Commit-Position: refs/heads/master@{#32922}