[flexiglass] Parameterize StackScrollAlgorithmTest

Some tests were failing with the flag on, and they needed their setup
steps to be updated to use values that are relevant in flexiglass.

Bug: 376236758
Test: atest StackScrollAlgorithmTest
Flag: com.android.systemui.scene_container
Change-Id: I1e6694afb37aacfbf05287fc90acd6884fd87597