Move `ScopedUnroot` and `ScopedInaccessible` to common_art_test.

Various tests in artd need these functions, so they have to be in a
common place. They can also be used in other tests, such as
oat_file_assistant_test.

Bug: 229268202
Test: m test-art-host-gtest-art_artd_tests
Change-Id: Ie644fd9217cdf7de400cd525165141f950122f0d
Merged-In: Ia71296fb9963f9e79036da9d84a7dbbd733e06a3
3 files changed