Revert "Make PUSHDATA opcodes have names in ParseScript"

Summary: This reverts commit fa7f0bba1284753a92fe8d6b68ffa284ccffb1b1.

Test Plan: N/A

Reviewers: deadalnix, schancel, #bitcoin_abc

Reviewed By: deadalnix, #bitcoin_abc

Subscribers: teamcity

Differential Revision: https://reviews.bitcoinabc.org/D1307