NIAP: Add a map to store the LTTKM

When do pairing, the set_encrypt_key_or_remove_key will be later than
get_key due to they are in different thread. Use a map to store them and
will check whether the key exist in map. If no, will get the key from
the JAVA bluetoothKeystore.

Bug: 148758680
Test: m
Change-Id: I044b11a231c6f65978019ce6092657c1bdd814d1
Merged-In: I044b11a231c6f65978019ce6092657c1bdd814d1