Optimization: Don't transform plain 'break' in 'switch' to a state machine.

Optimization: Don't transform plain 'break' in 'switch' to a state machine.

BUG=None
TEST=None

[usrbincc, 2013-03-23 21:57:54]

Simple fix (famous last words). Hope I didn't break anything.

#--cut--
dl_check() {
  local f=$(basename $1)
  test -e $f || curl -sO $1
  openssl sha1 < $f | grep -q "= $2" && return 0
  echo sha1 mismatch!
  return 1
}

git checkout f37adaa5ad9edef9   # last merge with branch master

git checkout -b issue7865048-break-continue-transformer-fix

cat > gen-switch.js <<"END"
function* G(n) {
  var a = yield n;
  switch (a) {
    case 42:
      break;
    default:
      a *= 2;
      // fall through
    case 21:
      a *= 100;
      break;
    case 11:
      throw new Error('went to ' + a);
  }
  yield a;
}
END

## before
./traceur --out gen-switch.out1.js -- gen-switch.js

dl_check https://codereview.appspot.com/download/issue7865048_1.diff \
  ba9e8a31c86d3f35 && git apply issue7865048_1.diff && make test

## after
./traceur --out gen-switch.out2.js -- gen-switch.js

## the switch statement remains untransformed.
diff -u gen-switch.out1.js gen-switch.out2.js
#--cut--

[arv, 2013-03-24 15:38:37]

LGTM

Committed as 0d4c5edb5b9388f60db3a31ea2bf471b58990afa