Fix PickerUriResolverTests with picker db enabled

As a unit test, we need to mock several operations in the test:
1. Binder calls to other processes (in another user)
2. FUSE synthetic path IO
3. Picker db querying for mimetype

Test: adb shell setprop sys.photopicker.pickerdb.enabled true
Test: atest PickerUriResolverTests
Bug: 195009139
Change-Id: I22fae1c563ef7d964ac60869b1e9fbbc2b56ab0f
4 files changed