Free allocation tracker hash map entries to reduce memory pressure

Use case:
A2DP playback becomes choppy after long hours of testing.

Steps:
1. installed 3rd party app that performs recurring LE scans.
2. Leave phone to run overnight.
3. After 24h+, connect a Bluetooth headset and music is very choppy.

Root cause:
The memory allocation tracker has support for double free check
where it stores all allocations in hash map but it never get
removed to track double free issue, A2DP memory allocation is
taking more time and leading to choppyness.

Fix:
Free the hash map entry to avoid memory leak from
allocation tracker.

Bug: 27621407
Change-Id: If57bd0b89c1d9b99c4f066c537a9e0fa49bc093f