Add patchoat test

The test checks that relocating an image using dex2oat and patchoat
yields the same ART file, except for OAT checksum and patch offset
delta.

Test: make test-art-host-gtest-patchoat_test
Bug: 66697305
Change-Id: I80f8b996bc8fc88ef798dceac9fd9ecd629045a3