port c1e7c8d9 (r32171)

  original commit message:
  This ensures that the ArgumentsAdaptorTrampoline does not clobber the
  new.target value, but rather passes it through to the callee unaltered.
  Note that callees do not yet use the new.target value so far.

  This is a preparatory CL to allows us passing new.target in a register
  instead of via a side-channel through the construct stub frame.

BUG=

Review URL: https://codereview.chromium.org/1475523002

Cr-Commit-Position: refs/heads/master@{#32192}