cherry pick pingcap#30696 to release-5.0

Signed-off-by: ti-srebot <ti-srebot@pingcap.com>

executor/builder.go

@@ -96,6 +96,23 @@ type MockPhysicalPlan interface {
 	GetExecutor() Executor
 }
 
+// MockExecutorBuilder is a wrapper for executorBuilder.
+// ONLY used in test.
+type MockExecutorBuilder struct {
+	*executorBuilder
+}
+
+// NewMockExecutorBuilderForTest is ONLY used in test.
+func NewMockExecutorBuilderForTest(ctx sessionctx.Context, is infoschema.InfoSchema, ti *TelemetryInfo, snapshotTS uint64, isStaleness bool, replicaReadScope string) *MockExecutorBuilder {
+	return &MockExecutorBuilder{
+		executorBuilder: newExecutorBuilder(ctx, is, ti, snapshotTS, isStaleness, replicaReadScope)}
+}
+
+// Build builds an executor tree according to `p`.
+func (b *MockExecutorBuilder) Build(p plannercore.Plan) Executor {
+	return b.build(p)
+}
+
 func (b *executorBuilder) build(p plannercore.Plan) Executor {
 	switch v := p.(type) {
 	case nil: