Added support for cl_ext_float_atomics in CBasicTestFetchMin/Max with atomic_float (#2353)

Related to #2142, according to the work plan, extending
`CBasicTestFetchMin`/`CBasicTestFetchMax` with support for atomic_float.

test_conformance/c11_atomics/common.h

@@ -24,8 +24,9 @@
 
 #include "CL/cl_half.h"
 
-#include <vector>
+#include <iomanip>
 #include <sstream>
+#include <vector>
 
 #define MAX_DEVICE_THREADS (gHost ? 0U : gMaxDeviceThreads)
 #define MAX_HOST_THREADS GetThreadCount()
@@ -892,14 +893,15 @@ CBasicTest<HostAtomicType, HostDataType>::ProgramHeader(cl_uint maxNumDestItems)
         header += std::string("__global volatile ") + aTypeName + " destMemory["
             + ss.str() + "] = {\n";
         ss.str("");
-
         if (CBasicTest<HostAtomicType, HostDataType>::DataType()._type
-            != TYPE_ATOMIC_HALF)
-            ss << _startValue;
-        else
+            == TYPE_ATOMIC_FLOAT)
+            ss << std::setprecision(10) << _startValue;
+        else if (CBasicTest<HostAtomicType, HostDataType>::DataType()._type
+                 == TYPE_ATOMIC_HALF)
             ss << static_cast<HostDataType>(
                 cl_half_to_float(static_cast<cl_half>(_startValue)));
-
+        else
+            ss << _startValue;
         for (cl_uint i = 0; i < maxNumDestItems; i++)
         {
             if (aTypeName == "atomic_flag")