Correct tuner native_handle handling.

*) releaseAvHandle
The fds in NativeHandle are owned by NativeHandle. They will be closed
in the NativeHandle's destructor. Because the native_handle_close is
called in MediaEvent, to avoid double close, the NativeHandle should be
duplicated.

*) getMediaEvent, handleAvShareMemory
The fds in NativeHandle would be closed in NativeHandle's destructor. To
keep using those fds, they should be duplicated.


Bug: 196232482
Test: atest android.media.tv.tuner.cts
Change-Id: I2b6c0d10d6896a192d7ff90119d4514d33eee72e