Add bootstrap065 unit test project.

This is the first of the bootstrap projects to use grail42's own test
framework (i.e. dogfood).
Implementation of test_part_combiner and basic unit tests for it.

Move a test registry mock class up into a common header.
Update to run_app.cmd

Add usage of grail42_android_faux_console_run_app_start_timeout env var.
Add policy based test_execution and remove previous stubs.

test_execution still need unit testing and not all policy classes have
been implemented yet.
Add a couple of missing typenames.
Android specific fixes.

Includes some hacks and bunch of #if 0'ed diagnostic code.

While this change does fix the Android specific issues, it is a big
steaming pile that needs significant cleanup.
Minor fix to test_part_combiner unit test for a failure on one platform.
Move test_part_mock out into own header for bootstrap065.
Add tests_executor and its unit tests and stub for test_executor.
For text_execution, provide partial implementation and unit test.

Updates to teat part logical thread holder.