Updating launch tests

Updating launch tests adding the check of WM and layer entries showing more than one consecutive time. Also renaming assertion to be more specific.

Test: atest FlickerTests:OpenAppWarmTest FlickerTests:OpenAppColdTest
Bug: b/171049683
Change-Id: I3a72a78496b2737d546c015ce13bbcbcc9b6b11c
4 files changed