solver: fixup generic result conversion

Somehow some duplicate code ended up in the exporter, resulting
in .Result() called twice on each ResultProxy when exporting multiple
Refs. The ConvertResult handles the conversions completely, so we don't
need the loop.

Signed-off-by: Justin Chadwell <[email protected]>

Author: jedevc

solver/llbsolver/solver.go

@@ -211,25 +211,6 @@ func (s *Solver) Solve(ctx context.Context, id string, sessionID string, req fro
 		if err != nil {
 			return nil, err
 		}
-		if res.Refs != nil {
-			m := make(map[string]cache.ImmutableRef, len(res.Refs))
-			for k, res := range res.Refs {
-				if res == nil {
-					m[k] = nil
-				} else {
-					r, err := res.Result(ctx)
-					if err != nil {
-						return nil, err
-					}
-					workerRef, ok := r.Sys().(*worker.WorkerRef)
-					if !ok {
-						return nil, errors.Errorf("invalid reference: %T", r.Sys())
-					}
-					m[k] = workerRef.ImmutableRef
-				}
-			}
-			inp.Refs = m
-		}
 
 		if _, ok := asInlineCache(exp.CacheExporter); ok {
 			if err := inBuilderContext(ctx, j, "preparing layers for inline cache", j.SessionID+"-cache-inline", func(ctx context.Context, _ session.Group) error {