Allow R targeting apps a legacy view

Allow R targeting apps to have a legacy view when accessing sdcard via
raw file paths temporarily.

This will let us bring back a986bc64

This will also let apps that target R and keep
the legacy flag to use raw paths continue to work until we enable FUSE

BUG: 137755945
BUG: 131432978
Test: atest CtsDeqpTestCases
Test: atest RestrictedPermissionsTest
Test: atest RestrictedStoragePermissionSharedUidTest
Change-Id: I0d49eca9d4e1769dcd3c0e2338db5b5e5a473032