Remove empty catch blocks

[GoodForOneFare]

Remove the empty catch block from code like this:

// Before
try {
  foo();
} catch (undefined) {} finally {
  bar();
}

// After
try {
  foo();
} finally {
  bar();
}

// Before
try {
  foo();
} catch (e) {} finally {
  bar();
}

// After
try {
  foo();
} finally {
  bar();
}

[xndyz]

@lemonmade and I decided it's easier to do this in another code-mod transform instead of Decaf (for the sake of sanity).

[xndyz]

Fixed in #153