Exception handling clean-up in TextToSpeech.java

This is just a code clean-up change. It should have no effects
on behavior.

- The exception clean-up code was copied in lots of places,
  added a restart() method for it.

- Use Log.e to print exception stack trace instead of doing
  it manually.

- Moved return statements outside finally-blocks. Having them
  in the finally-block makes no difference, but can be misleading.
  Also, Eclipse complains about it.

Change-Id: Ibfb18ca89d81d1fd8d212f29b6f8ab305b52ec49