Add more testing to ensure the sign bit is also testedfor equivalency

Author: fineg74

SYCL/ESIMD/regression/fmod_compatibility_test.cpp

@@ -64,13 +64,13 @@ int test_fmod(float x, float y) {
 
   float mod = std::fmod(ha, hb);
 
-  if (mod != out[0]) {
+  if (mod != out[0] || std::signbit(mod) != std::signbit(out[0])) {
     std::cout << "Vector test failed for " << x << " and " << y << "."
               << std::endl;
     return 1;
   }
 
-  if (mod != scalar_result) {
+  if (mod != scalar_result || std::signbit(mod) != std::signbit(scalar_result)) {
     std::cout << "Scalar test failed for " << x << " and " << y << "."
               << std::endl;
     return 1;