[FL-1816] Fix ble radio stack is alive check (#707)

* bt: fix bt_is_alive return, add bt_is_active
* bt: fix bt_is_alive return
* Cli: show heap usage in ps.
* FuriHal: strict sequence for flash operations
* Scripts: add stress test
* Core: proper heap calculation.

Co-authored-by: あく <alleteam@gmail.com>

core/furi/memmgr_heap.h

@@ -7,6 +7,8 @@
 extern "C" {
 #endif
 
+#define MEMMGR_HEAP_UNKNOWN 0xFFFFFFFF
+
 /** Memmgr heap enable thread allocation tracking
  * @param thread_id - thread id to track
  */