vpx_dec_fuzzer: add coverage for VP9D_SET_LOOP_FILTER_OPT
vpx_dec_fuzzer: add coverage for VP9D_SET_LOOP_FILTER_OPT

BUG=chromium:1076203

Change-Id: Ib3339a9fd7d940b69a5ef89b3fbf7f4fdeaac006

ShiftMediaProject/libvpx,ShiftMediaProject/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx,webmproject/libvpx,webmproject/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx,webmproject/libvpx