Add demux to mFrontendTests

aosp/2640754 adds a tuneFrontend call with testWithDemux enabled.
tuneFrontend() has some logic that calls DvrTests->openDvrInDemux()
which requires mDemux to be available, but mFrontendTests does not
have an associated demux. This CL adds a demux resource.

Bug: 317268814
Test: atest VtsHalTvTunerV1_1TargetTest
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:e7c5595ee5cfe79eb181e60399d8d857526d1af7)
Merged-In: I62ad038829ca3ed0ecc077527197eec444a5eb12
Change-Id: I62ad038829ca3ed0ecc077527197eec444a5eb12
diff --git a/tv/tuner/1.1/vts/functional/VtsHalTvTunerV1_1TargetTest.cpp b/tv/tuner/1.1/vts/functional/VtsHalTvTunerV1_1TargetTest.cpp
index ab51071..5377c45 100644
--- a/tv/tuner/1.1/vts/functional/VtsHalTvTunerV1_1TargetTest.cpp
+++ b/tv/tuner/1.1/vts/functional/VtsHalTvTunerV1_1TargetTest.cpp
@@ -35,6 +35,7 @@
     ASSERT_TRUE(mFrontendTests.setFrontendCallback());
     ASSERT_TRUE(mDemuxTests.openDemux(demux, demuxId));
     ASSERT_TRUE(mDemuxTests.setDemuxFrontendDataSource(feId));
+    mFrontendTests.setDemux(demux);
     mFilterTests.setDemux(demux);
     ASSERT_TRUE(mFilterTests.openFilterInDemux(filterConf.config1_0.type,
                                                filterConf.config1_0.bufferSize));