[strong] checking of this & super in constructors

R=dslomov@chromium.org, marja@chromium.org
BUG=v8:3956
LOG=N

Enforces for constructors that
- the only use of 'super' is the super constructor call
- the only use of 'this' is a property assignment
- both of these must happen at the top-level of the body
- 'this' may only be assigned after the 'super' call
- 'return' may only be used after the last assignment to 'this'

Not yet working for arrow functions (there might be deeper bugs with those).

Review URL: https://codereview.chromium.org/1024063002

Cr-Commit-Position: refs/heads/master@{#27977}