Split wm shell flicker tests into completely independent folders, which can be...

Split wm shell flicker tests into completely independent folders, which can be transferred to the respective teams.

This also allows the tests to be better configured, so that app compat tests don't run on phones

Bug: 307885357
Fixes: 307359855
Test: atest WMShellFlickerTestsPip1 WMShellFlickerTestsPip2 WMShellFlickerTestsSplitScreenGroup1 WMShellFlickerTestsSplitScreenGroup2 WMShellFlickerTestsService WMShellFlickerTestsBubbles WMShellFlickerTestsPlatinum
Change-Id: Ia17b04256becf04969223527e886a170dc11642b