Get rid of Trim().
Get rid of Trim().

Change-Id: I535347c72e5bf29ad3f20f44b74b90880813c336
Prog::Flatten() does the same thing when it finishes.
Reviewed-on: https://code-review.googlesource.com/4761
Reviewed-by: Paul Wankadia <62d4e38bb1380f055ec4b899baa75e52af09c5f7@google.com>

google/re2,google/re2,google/re2,google/re2,google/re2