Reducing time of TaplTests run

From ~245 to ~150 sec.

Done by removing testing behaviors that don't depend on QS from tests
marked with QuickstepOnOff attribute.

Also fixing a bug that went unnoticed: now restoring Launcher QS mode
after each test.

Bug: 110103162
Test: TaplTests suite
Change-Id: I715158b47ac1e370f578b8d4f13d9633283763fe