espeak: remove the espeak phonemeset data

Using the phonemes from the espeak dict_phonemes file does not
work as:

  1.  There are other phonemes like /_:/ that are not directly
      listed.

  2.  Phonemes have different behaviour in different contexts, e.g.
      /3:/ in en-sc maps to /VR/ when unstressed or when it has
      secondary stress.

  3.  The zh language does not provide any phonemes when using
      `espeak -x "[[PHONEME]]"`.

  4.  The mapping of phonemes varies depending on the accent in
      e.g. English with some mappings at the `espeak -x` level
      and some at the `espeak --ipa` level.

In addition, it is difficult to see from the generated files which
files are important to the tests and which are not.