Ensure that newly spawned task stack (dynamic) is getting freed up before
test completion and thus preventing false memory leak indication failure.
unit-test-app: add an API test_utils_task_delete
This API ensures that dynamic memory of deleted task gets freed up
before return. This helps for preventing false memory leak detections
in test failures.
Allocation of the temporary internal buffer will now repeat until a small enough buffer can be
allocated, and only fail if less than a 256 byte block of internal RAM is free.
Adds unit test for the same, and generic test utility for creating memory pressure.
New unity component can be used for testing other applications.
Upstream version of Unity is included as a submodule.
Utilities specific to ESP-IDF unit tests (partitions, leak checking
setup/teardown functions, etc) are kept only in unit-test-app.
Kconfig options are added to allow disabling certain Unity features.
