floor and ceil unnecessary calls to std::signbit removed

Author: ndgrigorian

dpctl/tensor/libtensor/include/kernels/elementwise_functions/ceil.hpp

@@ -69,7 +69,7 @@ template <typename argT, typename resT> struct CeilFunctor
             return in;
         }
         else {
-            if (in == 0 && std::signbit(in)) {
+            if (in == 0) {
                 return in;
             }
             return std::ceil(in);

dpctl/tensor/libtensor/include/kernels/elementwise_functions/floor.hpp

@@ -69,7 +69,7 @@ template <typename argT, typename resT> struct FloorFunctor
             return in;
         }
         else {
-            if (in == 0 && std::signbit(in)) {
+            if (in == 0) {
                 return in;
             }
             return std::floor(in);