Run test build: Create special HiddenApi shard.

Very few tests depend on hiddenapi so build them in their own shard.

This removes the hiddenapi dependency from all other shards,
which in turn removes the dependency on ART headers and C++ code.

Bug: 213297521
Test: ./art/test.py -b -r --host
Test: ./art/test.py -b -r --host -t 674-hiddenapi
Change-Id: I5d18d49b70bdaf9c3492ff4a82d32f7e9ba96873
5 files changed