Fix 'for (let i = foo; bar; baz) single statement;'.

- Fix indentation of 'var transformedForLoop = ...'.

BUG=https://github.com/google/traceur-compiler/issues/231
TEST=test/feature/Scope/BlockBinding11.js
Merge pull request #232 from usrbincc/block-binding-for-loop-single-statement

Block binding for loop single statement