tools/target_dec_fuzzer: set parser codec id to avoid assertion failure

Fixes: 9211/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_GSM_fuzzer-5680396581732352
Fixes: assertion failure

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpegSigned-off-by: Michael Niedermayer <michael@niedermayer.cc>

tools/target_dec_fuzzer.c

@@ -193,6 +193,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
         av_free(parser_avctx);
         return 0; // Failure of avcodec_open2() does not imply that a issue was found
     }
+    parser_avctx->codec_id = ctx->codec_id;
 
     FDBCreate(&buffer);
     int got_frame;