[android] fix untracked pid in Android (#3343)

src/posix/platform/hdlc_interface.cpp

@@ -121,9 +121,14 @@ exit:
     return error;
 }
 
+HdlcInterface::~HdlcInterface(void)
+{
+    Deinit();
+}
+
 void HdlcInterface::Deinit(void)
 {
-    assert(mSockFd != -1);
+    VerifyOrExit(mSockFd != -1);
 
     VerifyOrExit(0 == close(mSockFd), perror("close NCP"));
     VerifyOrExit(-1 != wait(NULL), perror("wait NCP"));

src/posix/platform/hdlc_interface.hpp

@@ -79,6 +79,12 @@ public:
      */
     explicit HdlcInterface(Callbacks &aCallbacks);
 
+    /**
+     * This destructor deinitializes the object.
+     *
+     */
+    ~HdlcInterface(void);
+
     /**
      * This method initializes the interface to the Radio Co-processor (RCP)
      *