Implement Negative Test for Platform Layer Functions (#1076)

* Implement Negative Tests for clPlatform Functions

This change introduces negative tests for clPlatform
functions as well as changes to the Harness to help with
other negative tests.

Signed-off-by: Chetankumar Mistry <chetan.mistry@arm.com>

* [SQUASH] Remove magic macro from Negative Platform Tests

This change removes the negative-testing macro and all
other changes related to its usage.

Signed-off-by: Chetankumar Mistry <chetan.mistry@arm.com>

test_conformance/api/CMakeLists.txt

@@ -2,6 +2,7 @@ set(MODULE_NAME API)
 
 set(${MODULE_NAME}_SOURCES
          main.cpp
+         negative_platform.cpp
          test_api_consistency.cpp
          test_bool.cpp
          test_retain.cpp