Complementation and modernization of commonfns tests (#1694)

* Unified common functions tests due to preparation for adding cl_khr_fp16 support

* Renamed base structure, few cosmetic corrections

* Added corrections due to code review

* Removed comment separators

* Added review related corrections

test_conformance/commonfns/CMakeLists.txt

@@ -3,22 +3,10 @@ set(MODULE_NAME COMMONFNS)
 set(${MODULE_NAME}_SOURCES
     main.cpp
     test_clamp.cpp
-    test_degrees.cpp
-    test_max.cpp
-    test_maxf.cpp
-    test_min.cpp
-    test_minf.cpp
+    test_unary_fn.cpp
     test_mix.cpp
-    test_radians.cpp
     test_step.cpp
-    test_stepf.cpp
     test_smoothstep.cpp
-    test_smoothstepf.cpp
-    test_sign.cpp
-    test_fmax.cpp
-    test_fmin.cpp
-    test_fmaxf.cpp
-    test_fminf.cpp
     test_binary_fn.cpp
 )