composer: vts: don't clear reader errors on teardown

Fixing a bug that caused Teardown to clear the errors before
checking them

Bug: 303735490
Test: presubmit
Change-Id: Ieb02ab3015fc21bcef6624f8f45c3b84549005c2
diff --git a/graphics/composer/aidl/vts/VtsHalGraphicsComposer3_TargetTest.cpp b/graphics/composer/aidl/vts/VtsHalGraphicsComposer3_TargetTest.cpp
index 3111647..5e45fd9 100644
--- a/graphics/composer/aidl/vts/VtsHalGraphicsComposer3_TargetTest.cpp
+++ b/graphics/composer/aidl/vts/VtsHalGraphicsComposer3_TargetTest.cpp
@@ -1401,7 +1401,6 @@
   protected:
     void TearDown() override {
         ASSERT_FALSE(mDisplays.empty());
-        const auto errors = mReader.takeErrors();
         ASSERT_TRUE(mReader.takeErrors().empty());
         ASSERT_TRUE(mReader.takeChangedCompositionTypes(getPrimaryDisplayId()).empty());