Mostly done, it works, but the temporary LABEL syntax still to be fixed.


mysql-test/r/sp-error.result:
  New test case for WL#2002 (GOTO).
mysql-test/r/sp.result:
  New test case for WL#2002 (GOTO).
  (Also corrected another test)
mysql-test/t/sp-error.test:
  New test case for WL#2002 (GOTO).
mysql-test/t/sp.test:
  New test case for WL#2002 (GOTO).
  (Also corrected another test)
sql/lex.h:
  New symbol GOTO.
  Also a temporary symbol LABEL, which hopefully will go away soon.
sql/sp_head.cc:
  Fixed backpatching to cope with free GOTO labels an hpop and cpop instructions.
  Also optimized away pointless jump instructions.
sql/sp_head.h:
  Fixed backpatching to cope with free GOTO labels an hpop and cpop instructions.
  We now sometimes generate hpop/cpop 0 instructions but the optimizer removes them.
sql/sp_pcontext.cc:
  Added free GOTO labels, and support for coping with jumps out of blocks
  with handlers or cursors.
sql/sp_pcontext.h:
  Added free GOTO labels, and support for coping with jumps out of blocks
  with handlers or cursors.
sql/sql_yacc.yy:
  Added GOTO and LABEL, and adjusted backpatching accordingly. Also fixed LEAVE
  out of blocks. The LABEL syntax will go away soon, hopefully.