Avoid crashing when failing graphics VTS

When the tests fail, ensure we continue running so we can run the
remainder of the tests.

Bug: 304976052
Test: atest GraphicsComposerAidlCommandTest
Change-Id: Ia6ab2bbd284bb7eddeb49164dcbe7285829ad9c3
diff --git a/graphics/composer/aidl/vts/VtsHalGraphicsComposer3_TargetTest.cpp b/graphics/composer/aidl/vts/VtsHalGraphicsComposer3_TargetTest.cpp
index 5ff420a..3111647 100644
--- a/graphics/composer/aidl/vts/VtsHalGraphicsComposer3_TargetTest.cpp
+++ b/graphics/composer/aidl/vts/VtsHalGraphicsComposer3_TargetTest.cpp
@@ -1400,6 +1400,7 @@
 class GraphicsComposerAidlCommandTest : public GraphicsComposerAidlTest {
   protected:
     void TearDown() override {
+        ASSERT_FALSE(mDisplays.empty());
         const auto errors = mReader.takeErrors();
         ASSERT_TRUE(mReader.takeErrors().empty());
         ASSERT_TRUE(mReader.takeChangedCompositionTypes(getPrimaryDisplayId()).empty());