Add more vintf_object_test

* Fix duplicated Compat2 test in libvintf_test
The test is duplicated in libvintf_test and vintf_object_test;
it also fails because details::CheckCompatibility doesn't take
GetXCompatibilityMatrix functions.

* Add PartitionMounter that allows mocking on mount
procedures

* Fix duplicated mount and unmount in checkCompatibility

Test: libvintf_test
Test: vintf_object_test

Change-Id: I07be537696efe64f084fdbed77a781b26e971784
Merged-In: I07be537696efe64f084fdbed77a781b26e971784
10 files changed