Disable the OSI allocation tracker.

Temporary disable the allocation tracker initialization
(even for BLUEDROID_DEBUG) when initializing Bluetooth.
This is a short-term workaround solution for several issues related to
the usage of the allocation tracker.

* Inconsistent usage of osi_malloc()/osi_calloc() and osi_free()
  - Within some of the Bluetooth-related unit tests we have two copies
    of the same libosi library: one copy statically linked against the
    unit test, and another dlopen() at runtime as part of bluetooth.default.so
    Each of those copy has its own static variables.
  - For the dlopen() copy we do call allocation_tracker_init(), while for the
    static copy within the unit test we don't call allocation_tracker_init()
  - Occasionally, there is a  memory allocation via osi_calloc()
    within the dlopen()-ed library, and then it is osi_free()-ed
    within the statically linked library.
 Such (mis)usage creates issues in two ways: (1) free()-ing incorrect
 pointer, and (2) the osi hash_map() in the dlopen()-ed library still considers
 the osi-tracked memory as allocated.
 NOTE: (1) could trigger random crashes, while (2) is the reason the unit
 test triggers an assert

* Avoid potential issues that could result from the fact that calling
  allocation_tracker_init() is not mandatory; i.e., the same
  issue described above could be triggered if osi_malloc()/osi_callod()
  was called before the call to allocation_tracker_init()

* There is still code that uses malloc(3)/calloc(3) and free(3) instead
  of osi_malloc()/osi_calloc() and osi_free()

Also, add missing pthread_mutex_lock()/pthread_mutex_unlock() guards,
and fix the allocation_tracker_uninit() implementation so it works
properly even if void allocation_tracker_init() wasn't called.

Bug: 21561735
Change-Id: Ic83d6cd40af1189c4ee9c1dbfd0ad8e4666e1502