Removed sp-goto.test, sp-goto.result and all (disabled) GOTO code.
  Also removed some related code that's not needed any more (no possible
  unresolved label references any more, so no need to check for them).
  NB: Keeping the ER_SP_GOTO_IN_HNDLR in errmsg.txt; it might become useful
      in the future, and removing it (and thus re-enumerating error codes)
      might upset things. (Anything referring to explicit error codes.)