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/device_execution/host_multi_queue.cpp

@@ -17,6 +17,7 @@
 #include <string.h>
 #include "harness/testHarness.h"
 #include "harness/typeWrappers.h"
+#include "harness/parseParameters.h"
 
 #include <vector>
 
@@ -25,7 +26,6 @@
 
 
 #ifdef CL_VERSION_2_0
-extern int gWimpyMode;
 static const char* multi_queue_simple_block1[] =
 {
     NL, "void block_fn(size_t tid, int mul, __global int* res)"