[CherryPick] Cherry pick #45916 #46031 #47299 (#47610)

* [ Dy2Static ] Fix bugs when select inputs meeting different shape or undefined-var (#45916)

* fix select_input with different shape errors:
1. select_input_with_buildin_type directly return non-undefinedvar branch when meeting undefined var
2. the output shape of select_input is inferred from inputs.

* reverse the logic in select_input

* [warning] added warning message in cond block when one branch returns variable and another returns None (#46031)

* [cherry-pick] Allow manaully set py_reader name in standalone executor (#45898) (#45931)

* Allow manaully set py_reader name in standalone executor

* [BugFix] while cond receives dict as input (#47299)

* fix bugs while cond receives dict as input

* add unittest

* change flatten -> _is_sequence_except_dict

* code format

Co-authored-by: feifei-111 <wuzhanfei@baidu.com>