Remove hiddenapi-blacklist.txt

Create an empty file in the build rule instead. Do not merged this
beyond AOSP. We have an implicitly built blacklist everywhere else.

Bug: 64382372
Test: make
Change-Id: I4e13e5daf635934a152d389a95bf45c482b5a87f
Merged-In: Ifa912f8751025b7de24a982a1a227a9c27d18267