[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>

firmware/targets/furi-hal-include/furi-hal-bt.h

@@ -19,6 +19,9 @@ void furi_hal_bt_start_advertising();
 /** Stop advertising */
 void furi_hal_bt_stop_advertising();
 
+/** Returns true if BLE is advertising */
+bool furi_hal_bt_is_active();
+
 /** Get BT/BLE system component state */
 void furi_hal_bt_dump_state(string_t buffer);
 
@@ -32,10 +35,10 @@ bool furi_hal_bt_wait_startup();
  * Lock shared access to flash controller
  * @return true if lock was successful, false if not
  */
-bool furi_hal_bt_lock_flash();
+bool furi_hal_bt_lock_flash(bool erase_flag);
 
 /** Unlock shared access to flash controller */
-void furi_hal_bt_unlock_flash();
+void furi_hal_bt_unlock_flash(bool erase_flag);
 
 /** Start ble tone tx at given channel and power */
 void furi_hal_bt_start_tone_tx(uint8_t channel, uint8_t power);