Replace node level check ASSERT_MSG_NODE()/FATAL_ERROR_NODE() with REQUIRE() or ERROR_IF()

- Adding return code enum class: {VALID, UNPREDICTABLE, ERROR}
- Runtime errors (e.g. memory allocation failure) will abort immediately, or will return one of the three return codes
  Part of the codes are re-written to pass REQUIRE() to the top-level (e.g. apply_scale_32/16())
- Update setExpectedFailure() to setExpectedReturnCode() on test generation script
- Update test regression script to interface with reference model change

Signed-off-by: Kevin Cheng <kevin.cheng@arm.com>
Change-Id: Ia063c936bcb2a54d6e379a5bb6801aa72d1186f1