test: re-enable duplex resampler coverage

Update tests for all-consumed input and zero-frame sizing.

Author: padenot

src/cubeb_resampler_internal.h

@@ -351,6 +351,9 @@ template <typename T> class cubeb_resampler_speex_one_way : public processor {
   uint32_t input_needed_for_output(int32_t output_frame_count) const
   {
     assert(output_frame_count >= 0); // Check overflow
+    if (output_frame_count == 0) {
+      return 0;
+    }
     int32_t unresampled_frames_left =
         samples_to_frames(resampling_in_buffer.length());
     float input_frames_needed_frac =