have_first_byte now implies run_forward.
have_first_byte now implies run_forward.

Change-Id: I88c88e17f7c3789744805c0039a67df7360d6b3e
Reviewed-on: https://code-review.googlesource.com/c/re2/+/56652
Reviewed-by: Paul Wankadia <62d4e38bb1380f055ec4b899baa75e52af09c5f7@google.com>

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