Form submitted from JS should not submit double values

Jquery validation adds hidden element and removes it after JS submit handler. In blink, it was resulting in extra value being submitted.

This patch reverts changes of r170520, r171008 and r169158.

r169158, changes are not needed anymore due to formcreate called from scheduleformsubmission.
r170520 and r171008 removed variable which control double form submission when from JS and normal submission.

Also fixes the issue with bug357101, which CL170520 fixed, by keeping validateInteractive independent of m_isSubmittingOrInUserJSSubmitEvent variable.

R=tkent, keishi
BUG=378949
TEST=Check add remove element from inside user JS event handler, does not lead to double value submission.

Review URL: https://codereview.chromium.org/449823003

git-svn-id: svn://svn.chromium.org/blink/trunk@179776 bbb929c8-8fbe-4397-9dbb-9b2b20218538