Don't exit too quickly when reporting an exception.

Don't exit too quickly when reporting an exception.

MWExceptionHander::handle() already exist at the end of its task,
so there's no need to have other die() calls.

There were some problems with that:
- wfLogProfilingData() was only called after reporting some exception
- MWExceptionHandler::report() was not consistent between web and
  command-linerequests
- MWException::reportHTML() was also not consistent when using the
  OutputPage object or not

Also removed MWExceptionHander::escapeEchoAndDie() since it's not needed anymore.

Change-Id: Ibb679c425ef0271a65f623c7b8541ec9bec70eb0