Added cl_khr_fp16 extension support for test_explicit_s2v from basic (#1713)

* Added cl_khr_fp16 support for test_explicit_s2v from basic (issue #142, basic)

* Cosmetic corrections

* cosmetic fix

* Added correction to distinguish signed and unsigned char types for ARM architecture tests

* Added missing pieces of convertion procedure to support half

* Corrected condition to verify if additional pragma is necessary (issue #142, basic)

* Add NaN check for half to float conversion

* check-format fixes

* Add NaN check for all float types

Use std::isnan for float/double types.

Change-Id: I005bddccaa3f8490ac59b2aa431ed315733ad143

* Fix Ubuntu build error with isnan macro definition

Change-Id: I671ed826a9631fbbc66d0aa9b674ab00124c7967

* Check format fixes

* NAN define not needed anymore

---------

Co-authored-by: Vasu Penugonda <vpenugon@qti.qualcomm.com>
Co-authored-by: Sreelakshmi Haridas <sharidas@quicinc.com>

test_conformance/basic/test_fpmath.cpp

@@ -33,7 +33,11 @@
 
 #include "procs.h"
 
-static const char *fp_kernel_code = R"(
+extern cl_half_rounding_mode halfRoundingMode;
+
+namespace {
+
+const char *fp_kernel_code = R"(
 %s
 __kernel void test_fp(__global TYPE *srcA, __global TYPE *srcB, __global TYPE *dst)
 {
@@ -42,8 +46,6 @@ __kernel void test_fp(__global TYPE *srcA, __global TYPE *srcB, __global TYPE *d
     dst[tid] = srcA[tid] OP srcB[tid];
 })";
 
-extern cl_half_rounding_mode halfRoundingMode;
-
 #define HFF(num) cl_half_from_float(num, halfRoundingMode)
 #define HTF(num) cl_half_to_float(num)
 
@@ -370,6 +372,8 @@ protected:
     std::map<size_t, std::string> type2name;
 };
 
+} // anonymous namespace
+
 int test_fpmath(cl_device_id device, cl_context context, cl_command_queue queue,
                 int num_elements)
 {