Optimization: Remove empty FallthroughState states.

Optimization: Remove empty FallthroughState states.

BUG=None
TEST=None

[usrbincc, 2013-03-23 21:37:18]

Another one that I've let sit too long.

This patch doesn't make as big a difference now that we use 'return' to
handle generator close.

#--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 -b issue7541050-statemachine-opt

cat > gen-empty-states.js <<"END"
function* G(n1, n2) {
  for (var i = n1; i < n2; i++) {
    yield i;
    if (i % 42 === 0)
      break;
  }
}
END

## before
./traceur --out gen-empty-states.out1.js -- gen-empty-states.js

dl_check https://codereview.appspot.com/download/issue7541050_1.diff \
  526ec7a4f0dcfd71 && git apply issue7541050_1.diff && make test

## after
./traceur --out gen-empty-states.out2.js -- gen-empty-states.js

## the empty state is gone.
diff -u gen-empty-states.out1.js gen-empty-states.out2.js
#--cut--

https://codereview.appspot.com/7541050/diff/1/src/codegeneration/generator/Ge...
File src/codegeneration/generator/GeneratorTransformer.js (right):

https://codereview.appspot.com/7541050/diff/1/src/codegeneration/generator/Ge...
src/codegeneration/generator/GeneratorTransformer.js:203:
this.removeEmptyStates(machine.states),
State machine manipulation functions like this should probably all be
moved to a utility library eventually.

[arv, 2013-03-24 15:01:53]

LGTM

I changed the continue to if/else before committing.

Committed as aa3ae4930eeb9c46445924393d771c573ac79058

https://codereview.appspot.com/7541050/diff/1/src/codegeneration/generator/CP...
File src/codegeneration/generator/CPSTransformer.js (right):

https://codereview.appspot.com/7541050/diff/1/src/codegeneration/generator/CP...
src/codegeneration/generator/CPSTransformer.js:427: continue;
You can do if/else instead here

[usrbincc, 2013-03-25 18:29:52]

https://codereview.appspot.com/7541050/diff/1/src/codegeneration/generator/CP...
File src/codegeneration/generator/CPSTransformer.js (right):

https://codereview.appspot.com/7541050/diff/1/src/codegeneration/generator/CP...
src/codegeneration/generator/CPSTransformer.js:432: for (i = 0; i <
newStates.length; i++) {
Oops, just realized this for loop is O(n^2). I'll fix this in a
follow-up.