[Dev options] Remove the use of java.lang.System.setProperty

java.lang.System properties are not shared amongst processes and does
not work as intented system level caching mechanism

Test: Updated tests
Bug: 348193756
Flag: com.android.window.flags.show_desktop_windowing_dev_option
Change-Id: I4969b1c67bc37a1ba45e0c30e43defd323079229
4 files changed