Build: Split NS and Secure regression tests build

Seperate NS and Secure regressin test builds.

  - TF-M secure build integrates secure regression tests and test
    services via test/secure_regression.
  - Non-secure regression tests are built via test/ns_regression.
  - Pass tf-m-tests test config to TF-M secure build via argument
    CONFIG_TFM_TEST_CONFIG_FILE.
  - Fix issues when no regression test is enabled.

Signed-off-by: David Hu <david.hu@arm.com>
Change-Id: I1e550bf6d6a36a220275743c3312a61f7ae2c78e
43 files changed