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=v8:4280
LOG=N

Review URL: https://codereview.chromium.org/1512543002

Cr-Commit-Position: refs/heads/master@{#32906}