Remove recursion regexpMatchTree
Remove recursion regexpMatchTree

Before, we would have a special type that translates

  regexp:"abc.*def"

into

  (AND regexp:"abc.*def" substr:"abc" substr:"def")

now, construct the AND directly using andMatchTree.

Change-Id: Ib83baad0aa6dbcc18a99df0b17d59297c4b4a52f

google/zoekt,google/zoekt