ProCamera: Fix memory leak in consumeFrameMetadata

Bug: 8402301
Change-Id: I975990185f45bb8552712271b9ac457af08a170c
diff --git a/camera/tests/ProCameraTests.cpp b/camera/tests/ProCameraTests.cpp
index ecc0854..87f817a 100644
--- a/camera/tests/ProCameraTests.cpp
+++ b/camera/tests/ProCameraTests.cpp
@@ -1021,6 +1021,9 @@
     // Consume two frames simultaneously. Unsynchronized by timestamps.
     for (int i = 0; i < REQUEST_COUNT; ++i) {
 
+        // Exhaust event queue so it doesn't keep growing
+        while (mListener->ReadEvent() != UNKNOWN);
+
         // Get the metadata
         EXPECT_OK(mCamera->waitForFrameMetadata());
         CameraMetadata meta = mCamera->consumeFrameMetadata();