Add singleton rule for hiddenapi list generation

The lists of public/private APIs used for non-SDK API restriction
enforcement used to be generated by Doclava. In Q we're switching
to resolving android.jar (and other SDK stub JARs) against the boot
class path directly to avoid lowering Doclava's high-level view of
the framework and issues related to it.

This patch adds a new build rule which invokes `hiddenapi` on all
boot class path dex files simultaneously. The tool generates two
text files - one with public and one with private APIs.

Bug: 79409988
Test: m out/target/common/obj/PACKAGING/hiddenapi-private-list.txt
Merged-In: I826d8ac513a41a1d6d5e29a8300073158cff5acf
Change-Id: I826d8ac513a41a1d6d5e29a8300073158cff5acf
(cherry picked from commit a39db485)