Revert BidiResolver::createBidiRunsForLine changes

Revert the following changes (temporarily):
  r179177 e328f38 "Have BidiRunList destructor delete runs"
  r179068 db7714a "Fix loop condition in BidiRunList::replaceRunWithRun"
  r178879 2b6511b "Change BidiResolver::createBidiRunsForLine to take r"

The change to BidiResolver in r178879 caused a bug in the handling of
isolates in certain edge cases that is proving more complicated than
expected to fix. Rather than leaving things partially broken on trunk
this change reverts the change in question. Once I've come up with a
satisfactory solution I plan to reland the changes mentioned above.

R=leviw@chromium.org
BUG=398339

Review URL: https://codereview.chromium.org/433923003

git-svn-id: svn://svn.chromium.org/blink/trunk@179342 bbb929c8-8fbe-4397-9dbb-9b2b20218538