[fix](olapscanner) fix coredump caused by concurrent acccess of olapscan node _conjuncts

be/src/vec/exec/scan/new_olap_scan_node.cpp

@@ -513,6 +513,7 @@ Status NewOlapScanNode::_init_scanners(std::list<VScannerSPtr>* scanners) {
                 key_ranges, rs_readers, rs_reader_seg_offsets, _need_agg_finalize,
                 _scanner_profile.get());
 
+        RETURN_IF_ERROR(scanner->prepare(_state, _conjuncts));
         scanner->set_compound_filters(_compound_filters);
         scanners->push_back(scanner);
         return Status::OK();

be/src/vec/exec/scan/new_olap_scanner.cpp

@@ -103,10 +103,13 @@ static std::string read_columns_to_string(TabletSchemaSPtr tablet_schema,
     return read_columns_string;
 }
 
+Status NewOlapScanner::prepare(RuntimeState* state, const VExprContextSPtrs& conjuncts) {
+    return VScanner::prepare(state, conjuncts);
+}
+
 Status NewOlapScanner::init() {
     _is_init = true;
     auto parent = static_cast<NewOlapScanNode*>(_parent);
-    RETURN_IF_ERROR(VScanner::prepare(_state, parent->_conjuncts));
 
     for (auto& ctx : parent->_common_expr_ctxs_push_down) {
         VExprContextSPtr context;

be/src/vec/exec/scan/new_olap_scanner.h

@@ -65,6 +65,8 @@ class NewOlapScanner : public VScanner {
 
     Status close(RuntimeState* state) override;
 
+    Status prepare(RuntimeState* state, const VExprContextSPtrs& conjuncts);
+
     const std::string& scan_disk() const { return _tablet->data_dir()->path(); }
 
     void set_compound_filters(const std::vector<TCondition>& compound_filters);