Added --editMode option to parse.js and parserTests.js

* This turns off autoInserted* flags in the the serializer.
  Enabling this mode will cause more parser tests to fail
  as well as add a lot more noise to roundtrip-testing.

  Selective serialization automatically disables the use of these
  flags. Production deploy in the live editing scenario will also
  disable the flags.

* Running parserTests in editMode seems to lead to 17 additional
  wt2wt test failures.

Change-Id: Iaa3b1bf17d8068d21d87153837ab97b61448dcda