In some cases launcher is not ready at test creation, in computeTestMethods

This causes the tests to fail, instead use TAPL only when first used to prevent

Stack:java.lang.AssertionError: http://go/tapl test failure: Launcher content provider is still not enabled;

Fixes: 315061537
Test: <flicker tests in presubmit>
Change-Id: Idf8bb12693234a4a92af815f36267314388cc9f5