[ Merge of http://go/wvgerrit/153669 ] The oemcrypto_decrypt_cenc_fuzz fuzz test found a null reference error. This adds a check to ensure that the input_buffer vector used for the sample descriptions is not empty before attempting to access it. Bug: 192310854 Bug: 236317198 Change-Id: If3909b01d3bc19434bbd5b6b77e7cd76182b2bdf