Refactor wimpy feature (#2507)

- Make it a common parameter in harness using either '-w', '--wimpy' or
'CL_WIMPY_MODE' environment variable.
- Remove all test specific wimpy variable.

---------

Co-authored-by: Kévin Petit <kpet@free.fr>

test_conformance/math_brute_force/utility.h

@@ -23,6 +23,7 @@
 #include "harness/testHarness.h"
 #include "harness/ThreadPool.h"
 #include "harness/conversions.h"
+#include "harness/parseParameters.h"
 #include "CL/cl_half.h"
 
 #define BUFFER_SIZE (1024 * 1024 * 2)
@@ -60,7 +61,6 @@ extern cl_mem gOutBuffer2[VECTOR_SIZE_COUNT];
 extern int gSkipCorrectnessTesting;
 extern int gForceFTZ;
 extern int gFastRelaxedDerived;
-extern int gWimpyMode;
 extern int gHostFill;
 extern int gIsInRTZMode;
 extern int gHasHalf;