Revert "lavfi/buffersrc: push the frame deeper if requested."

Fixes framesync filters with shortest option enabled.

This reverts commit 0ff5567a.

libavfilter/buffersrc.c

@@ -173,20 +173,6 @@ int attribute_align_arg av_buffersrc_add_frame_flags(AVFilterContext *ctx, AVFra
     return ret;
 }
 
-static int push_frame(AVFilterGraph *graph)
-{
-    int ret;
-
-    while (1) {
-        ret = ff_filter_graph_run_once(graph);
-        if (ret == AVERROR(EAGAIN))
-            break;
-        if (ret < 0)
-            return ret;
-    }
-    return 0;
-}
-
 static int av_buffersrc_add_frame_internal(AVFilterContext *ctx,
                                            AVFrame *frame, int flags)
 {
@@ -199,11 +185,6 @@ static int av_buffersrc_add_frame_internal(AVFilterContext *ctx,
     if (!frame) {
         s->eof = 1;
         ff_avfilter_link_set_in_status(ctx->outputs[0], AVERROR_EOF, AV_NOPTS_VALUE);
-        if ((flags & AV_BUFFERSRC_FLAG_PUSH)) {
-            ret = push_frame(ctx->graph);
-            if (ret < 0)
-                return ret;
-        }
         return 0;
     } else if (s->eof)
         return AVERROR(EINVAL);
@@ -258,12 +239,6 @@ static int av_buffersrc_add_frame_internal(AVFilterContext *ctx,
     if ((ret = ctx->output_pads[0].request_frame(ctx->outputs[0])) < 0)
         return ret;
 
-    if ((flags & AV_BUFFERSRC_FLAG_PUSH)) {
-        ret = push_frame(ctx->graph);
-        if (ret < 0)
-            return ret;
-    }
-
     return 0;
 }