[0001] Fix segfault from double tuner closure

The JNI nativeClose() does not support closing twice. The tuner SP is
set to null. On the second usage, it derefs it. Although the app
shouldn't close the tuner twice, it solves the double close() issue from
the CTS.

Bug: 356779633
Test: atest android.media.tv.tuner.cts.TunerTest on cuttlefish
Flag: EXEMPT bugfix

(cherry picked from https://android-review.googlesource.com/q/commit:394903a386df2289c8320e9566f7396730a16c12)
Merged-In: Ie4abdc5bf6cdcc6265383a76cfa671e06accc1a2
Change-Id: Ie4abdc5bf6cdcc6265383a76cfa671e06accc1a2