Re-enable libsnapshot ImageManagerTest

ImageManagerTest had been temporarily disabled because flaky.
This test looks stable now, re-enable it.

Bug: 148889015
Test: atest vts_libsnapshot_test [-- --abi x86]
Signed-off-by: Alessio Balsini <balsini@google.com>
Change-Id: I858661fed7f58d1e2857ed88f5d8e0f5220bf8c2
(cherry picked from commit 42a608162db37f62727ad8c163440776e7b37aaa)
Merged-In: I858661fed7f58d1e2857ed88f5d8e0f5220bf8c2
1 file changed