Push down limit to SortPreservingMergeExec and SortPreservingMergeStream #6000

graph LR;
    SPME[SortPreservingMergeExec]-->spwn_handler-->SE[SortExec];
    SPME[SortPreservingMergeExec]-->streaming_merge-->SPMS[SortPreservingMergeStream];
    SE-->execute-->do_sort-->ExternalSort-->insert_batch-->sort_batch-->lexsort_to_indices;
    insert_batch-->spill-->in_mem_partial_sort-->get_sorted_iter-->lexsort_to_indices;
    ExternalSort-->sort-->streaming_merge;
    sort-->in_mem_partial_sort;

    style SPME color:red
    style streaming_merge color:red
    style SPMS color:red
    style spwn_handler color:green
    style SE color:green
    style execute color:green
    style do_sort color:green
    style ExternalSort color:green
    style insert_batch color:green
    style sort_batch color:green
    style lexsort_to_indices color:green
    style sort color:green
    style in_mem_partial_sort color:green
    style get_sorted_iter color:green
    style spill color:green