In this commit, we modify regular filter construction slightly. Rather
than including each pushed data in the script, we instead just include
the script directly, which will eventually be hashed. The rationale for
doing this is two-fold:
* Most scripts today and in the foreseeable future will just be a
commitment.
* Including only the script itself and not the hash of the script
reduces the worst case filter size. Otherwise, an attacker could
include a bunch of 2 byte push datas and blow up the filter size for
all nodes.
